Heating, Ventilating and Air conditioning The book of abstracts of ...

The 5th International Conference on Heating, Ventilating and Air conditioning

The book of abstracts of

The 5rd International Conference on Heating, Ventilating and Air Conditioning

10-12 June 2014, Olympic Hotel Tehran-Iran

(400-word Abstracts)

www.hvac-conference.ir

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Organized by: Building and Housing Research Center The Iranian Construction Engineering Organization The Iranian e-Community of Mechanical Engineers University of Tarbiyat Modares In partnership with: United Nations Environment Program (UNEP) Turkish Society of HVAC & Sanitary Engineers (TTMD) In Cooperation with: Institute of Standard and industrial Research of Iran The Iranian Society of Consulting Engineers The Iranian Syndicate of M&E and Industrial Contractors

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The Iranian Combustion Institute The Syndicate of Radiator and Air Conditioners Iranian Engineering Society of Cooling & Heating Sponsored by: Iran Radiator Industrial Group Butane Industrial Group Giti Pasand Industrial Group Tahvieh Co. Pazhand Pad Co. Dama Ariya Co.

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Media Sponsors:

Air Conditiong Magazine Heating, Ventilating and Air Conditioning Newsletter

Event manager: Aria Group

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Scientific Committee:

Prof. Abbas Abbasi (Amirkabir University of Technology – Iran) Mr. Ayub Adeli (Iranian Combustion Institute) Dr. Cyrus Aghanajafi (K N Toosi University – Iran) Dr. Abolfazl Ahmadi (Iranian University of Science and Technology – Iran) Prof. Mohammad A. Akhavan (University of Tehran – Iran) Dr. Ali Akbar Alam Rajabi (Esfahan University of Technology-Iran) Dr. Majid Amidpour (K N Toosi University – Iran) Dr. Mohammad Reza Ansari (Tarbiat Modares University – Iran) Prof. Mahmoud Arab Yaghoubi (University of Shiraz – Iran) Prof. Mehdi Ashjaei (University of Tehran – Iran) Prof. Mehdi Bahadorinejad (Sharif University of Technology – Iran) Dr. Farzad Bazdidi Tehrani (Iranian University of Science and Technology – Iran) Dr. Mehdi Bidabadi (Iranian University of Science and Technology – Iran) Dr. Shahram Delfani (Building and Housing research Center – Iran) Mrs. Parichehr Ghezelbash (The Institute of Standards & Industrial Research of Iran) Mr. Asghar Haj Saghati (Iranian Solar Energy Society) Prof. Ghassem Heidarinejad (Tarbiat Modares University – Iran) Dr. Mostafa Hosseinalipour (Iranian University of Science and Technology – Iran) Prof. Mohammad Hosni (Kansas State University – USA) Dr. Mansour Jadidi (Shahid Rajai University – Iran) Dr. Ali Jafarian Dehkordi (Tarbiat Modares University – Iran) Dr. Vali Kalantar (Yazd University-Iran) Mr. Babak Kamkari (University of Tehran-Iran) Dr. Farzad Jafarkazemi (Islamic Azad University – Iran) Dr. Abdol Razagh Kabinejadian (Iranian Society of HVAC Engineers -Iran) Dr. Hossein Khorasanizadeh (Kashan University-Iran) Prof. Farshad Kosari (University of Tehran-Iran) Dr. Mostafa Mafi (University of Qazvin-Iran) Dr. Mehdi Maerefat (Tarbiat Modares University – Iran) Prof. Kiumars Mazaheri (Tarbiat Modares University – Iran) Prof. Mozafar Ali Mehrabian (Bahonar University of Kerman – Iran) Prof. Mohamamd Moghiman (Ferdowsi University of Mashad – Iran) Mr. Heshamatolah Monsef (Piraz Consultants Co. – Iran) Mr. Manuchehr Motamedi (Jarvand Co. - Iran) Prof. Mojtaba Mousavi Nainian (K N Toosi University – Iran) Dr. Amir Omidvar (Shiraz University of Technology-Iran) Dr. Hadi Pasdarshahri (Tarbiat Modares University – Iran) Dr. Majid Sabzpoushani (Kashan University-Iran) Prof. Majid Saffar Aval (Amirkabir University of Technology – Iran)

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Prof. M. H. Saidi (Sharif University of Technology – Iran) Dr. Sorena Sattari (Sharif University of Technology – Iran) Dr. Mohammad Behashd Shafie (Sharif University of Technology – Iran) Dr. Ghanbar Ali Sheykhzadeh (Kashan University-Iran) Dr. Asghar Shirazpour (Iranian Construction Engineering Organization – Iran) Prof. Hossein Shokouhmand (University of Tehran – Iran) Dr. Alireza Zolfaghari (Bojnourd University) Dr. Saeid Zeinali Heris (University of Mashad)

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Session No. 1

New design criteria in HVAC&R

Tuesday, June 11- 14:00-16:00 Room: Tosan

Chairman (s): Dr. Hossein Shokouhmand- Dr. Hadi Pasdarshahri

Title Paper No.

Present a new approach to reduce the risk of condensation in radiant cooling system in different climates of Iran Navid Morovat, Mehdi Maerefat

1106

Design and 3D Simulation of Tabriz Subway Ventilation Systems With Investigation of The Effect Air Washer

Seyyed Hamed Adibi, Moharram Jafari

4123

Numerical study on the effect of inlet air flow rate on thermal comfort and indoor air quality in a displacement ventilation system a

Mohammad Hassan Fatollahzadeh, Ghassem Heidarinejad, Hadi Pasdarshahri

6108

Optimization of tunnel ventilation by computational fluid dynamic

Sahar Hassanpour, Mahdi Moghimi 3108

Check silencer and air systems provide two new optimized designs with software Fluent

Mohamma morad sheyki, meysam kheyri amnab

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Session No. 2

Indoor air quality and comfort conditions

Tuesday, June 11- 14:00-16:00 Room: Golshan

Chairman(s): Dr. Mohammad Zabetian- Dr. Jamasak Pirkandi

Paper Title Paper No. Impact of LAF system design factors on contaminant removal and thermal comfort in the operating room HVAC system using OpenFOAM

Mojtaba Amiraslanpour, Jafar Ghazanfarian

6110

Application of Floor Heating System in New Generation Sustainable Green Domes

Taha Khademinejad, Shahab Rahimzadeh, Pouyan Talebizadeh, Hassan Rahimzadeh

6111

Thermal and Ventilation Performance of a Typical Office in a Hot Humid Climate

Roonak Daghigh1, Nor Mariah Adam2

6113

Numerical Comparison of Airborne Particles Deposition and Dispersion in a Room with Different Heating Systems

Hamidreza Golkarfard

6116

Energy efficient office building concept for Latvian climate

Anatolijs Borodinecs, Egils Dzelzitis, Juris Sorokins

7137

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http://www.sciencedirect.com/science/article/pii/S0378778812006251


Session No. 3

Industrial HVAC&R, Energy optimization

Tuesday, June 11- 16:30-18:00 Room: Tosan

Chairman (s): Dr. Ghasem Heidari Nezhad- Dr. Babak Kamkari

Title Paper No.

Experimental and numerical investigation of thermal storage in a rectangular enclosure filled with phase changed material

Hossein Shokouhamnd, Babak Kamkari, Ramin Karami, Farshad Kowsary,

Mohammad Ali Akhavan-Behabadi

4124

Simulation of leakage and its effects on performance of rotary air preheater a

E. Hajidavalloo, A. Heidari, M. Shayan, T. Mahmoudi Parsa

3102

Improving hybrid desiccant cooling cycle for tropical areas a

Seyed Zia Miri, Ghassem Heidarinejad, Hadi Pasdarshahri 1128

Optimization of Office Building Facades with GPSPSOCCHJ Algorithm a

Mona Khatami, Maria kordjamshidi, Behrouz MohammadKari, Seyedalireza Zolfaghari 7123

-- 7131

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Session No. 4

Environmentally friendly air-conditioning, cooling and refrigeration techniques and Industrial HVAC&R

Wednesday, June 12- 08:30-10:00 Room: Tosan

Chairman(s): Dr. Shahram Delfani

Title Paper No.

An experimental study of condensed convective flow patterns in the downward U-shaped tubes with different inclinations

Moslem Mozafari, M.A. Akhavan-Behabadi, M. Jamali Ashtiani

5106

Experimental study of tube inclination and vapor quality effects on boiling heat transfer coefficient of refrigerant R-134a inside Corrugated coiled Tube

Mehdi Esmailpour , M.A. Akhavan-Behabadi , M. Jamali Ashtiani

5107

Theoretical analysis of natural refrigerants as substitutes in two-stage cascade refrigeration system

Mostafa Mafi, Morteza Shomali, Amirhosein Moradi

5109

The effect of water with various hardnesses on the performance of heating and cooling piping systems

Asieh Otaredi-Kashani, Shahram Delfani

3109

The effect of water softeners of resin , RO and electromagnetic on performance of heating and cooling system

Asieh Otaredi-Kashani, Shahram Delfani

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Session No. 5


Wednesday, June 12- 11:00-12:30

Room: Tosan

Chairman(s): Dr. Mehdi Marefat

Paper Title Paper No.

Performance Analysis of CCHP Systems for a Typical Building in Different Atmospheric Conditions of Iran

Ramin Karami , Masihollah Mahmoudpour ,Farzad Najafi

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Evaporating heat transfer of R-600a: An experimental study of the major parameters affecting heat-transfer

Saeed Baqeri, M.A. Akhavan-Behabadi, M. Nasr

1118

Numerical And Experimental Investigation On The Flow Efficiency In Perforated Dimple-Louvered Fins Banks In Compact Heat Exchangers

H. Shokuhmand, M. Ashjaee, F.Sangtarash

1119

Flow Boiling Heat Transfer of R-134a inside a Smooth Tube with Different Tube Inclinations

S.G. Mohseni, M.A. Akhavan-Behabadi

1120

CFD Study on the Air-Side Thermohydraulic Performance of Microchannel Heat Exchanger

Ehsan Gholamalizadeh, Man-Hoe Kim

6122

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Session No. 6

Energy optimization Wednesday, June 12- 14:00-15:30

Room: Tosan

Chairman (s): Dr. Abbas Abbasi- Dr. Jamasab Pirkandi

Title Paper No.

Evaluation of the Influence of Exterior Façade on the Annual Energy Consumption of Building in Shiraz and Esfehan Climates

Alireza Zolfaghari, Mehran Saadati-Nasab, Elaheh Norouzi

7119

Analysis and optimization of air flow through a vertical channel under different thermal boundary conditions

Mostafa Rahimi, Milad Khalafi Solout

7124

Investigation of Combined Heat and Power Generators into Residential Buildings based Polymer Exchange Membrane Fuel Cell a

Ebrahim Afshari, Hossein Motaharpoor

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Evaluation of turbulence models to simulate air flow in a space with near the floor height air distribution a

Mohammad Hassan Fatollahzadeh, Ghassem Heidarinejad, Hadi Pasdarshahri

6107

Simulation and analysis of Stirling engines, to increase efficiency, use of waste heat

Mostafa mahmoodi, Jamasb pirkandi, Seyeed ahmad ghavami 7120

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Session No. 7

Indoor air quality and comfort conditions

Sustainable zero and low-energy buildings

Wednesday, June 12- 16:30-18:00

Room: Tosan

Chairman(s): Dr. Mahdi Marefat

Title Paper No.

Numerical Investigation of thermal performance of optimum Trombe wall

Mehran Rabani, Vali Kalantar, Ahmadreza K.Faghih, Aliakbar Dehghan 1107

-- 2103 Numerical simulation of thermal comfort in a historical building – Case study: Tabatabayi House

Mahya Nazari, Ghassem Heidarinejad

6121

Comprehensive design of a nearly zero energy office building

Farzad Rezvani, Hasan Naderi, Farhad Minaie, Gholamreza Nasiri 8109

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Session No. 8


Application of renewable energies in HVAC&R

Thursday, June 13- 08:30-10:00

Room: Tosan

Chairman(s): Dr.Shahrmam Delfani- Dr. Farzad Jafar Kazemi

Title Paper No.

---- 1108 Analysis the effects of time variations of thermal penetration depth on the acquired power from the underground air-soil channels Mozhgan Nikoudel,Alireza Zolfaghari, Hossein Vatanpoor

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Experimentally analysis of airflow pattern and temperature distribution in heating a room with floor heating and radiator

Mostafa Rahimi, Mehrzad E’tezadi

6119

Analysis the effect of the green roof on annual energy consumption in Tehran climate

Alireza Zolfaghari, Mehran Saadati-Nasab, Elaheh Norouzi 7130

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Session No. 9


Energy Optimization

Thursday, June 13- 11:00-13:00

Room: Tosan

Chairman(s): Dr. Mohammad Hasan Saiedi- Dr. Mostafa Mafi

Title Paper No.

------- 3107

Sensitive analysis of dual expander C1/N2 and single mixed refrigerant processes to feed gas compositions changes in small-scale LNG plants

Amirhosein Moradi, Mostafa Mafi, Mansor Khanaki

4113

Prediction of Thermodynamic Properties of Gas-Helium from 10 to 1500 K and at Pressures up to 100 MPa using fundamental equations of state

Mohammad Maboudi, Masoud Ziabasharhagh

4114

Thermodynamic analysis and optimization of a novel ejector- cascade refrigeration cycle

Damoon Aghazadeh Dokandari, Seyyed Mohammad Seyyed Mahmoudi, Alireza Setayesh Hagh

7103

Experimental study of the effect of wind direction on the induced air flow rate in a two-sided wind-catcher

Mohammad Afshin, Ahmad Sohankar, Mojtaba Dehghan Manshadi, Mohammad Kazemi Esfeh

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Poster Session Wednesday, June 12

10:30-11:00

Paper No.

Title

1113 Validation of air zonal method for thermal analysis of a building with a double skin facade Mohammad Reza Daneshgar, Navid Latifian, Abdollah Avara, Ehsan Daneshgar

1117 CCHP economic analysis for the hotel buildings in Different Climate zones Farzad Najafi, Masihollah Mahmoudpour, Ramin Karami, Mohammad Ayazi

1125 Heat transfer performance and exergy analysis of corrugated plate heat exchanger using nanofluids Malek Khalouei, Majid Gholinejad, Iman Mortezaee

2104 Investigation of Energy Consumption and Energy Label in 40 Office Buildings in Tehran Hasan Naderi Mahabadi,Farnoush Rezvani, Farhad Minaee, Gholamreza Nasiri

3105 Economic Performance Analysis of a CHP System Based on Micro Gas Turbine using Lazaretto method Somayeh Pirkandi, Abdolreza Hatamlou, Jamasb Pirkandi

3106 ----

4106 Energy andexergy analysis of cogenerationcooling, heating and powersystemwiththe primarydrivers ofdiesel engine Mohsen Fallah, Ali Naseri

4107 Heating, Ventilating and Air-Conditioning(HVAC) Discharge Air TemperatureControl using Generalized Predictive Controller(GPC) for improvement of energy efficiency in buildings Alireza Adhami, Fatemeh Doosti, Amin Farmanbordar

4111

Making Dimensionless Inlet Variables to Present a General Approach forAnalysis Indirect Evaporative Cooling Counter-flow and Cross-Flow Heat Exchangers Ali Sohani, Hamidreza Hasani-Baliani, Hoseyn Sayyaadi

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Poster Session Wednesday, June 12

14:30-15:00

Paper No.

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7117 Thermodynamic and Thermo Economic Optimization of Combined Cycle Power Plant of Shiraz Masoud Ziabasharhagh, Bahram Ghorbani, Mohammad Rezaei

7125 Importance of Energy Conservation Policies in Building Sector in Iran & other countries With Approach to Energy Subsidies Decline in this sector A. Moradi

7133 Courtyard geometry optimization in different climatic region of Iran Zobeideh Bayat, Jamal khodakarami, Nazanin Nasrollahi

9110 Photovoltaic- thermal systems and applying them for electric generation and bulding heating Behrooz Mirzaeiziapour, Vahidpalideh, Naser Yadegari, Mohsen bagherikhalili

9111 Thermodynamic analysis of a compression-absorption refrigeration system assisted by geothermal energy in Ramsar Arvin AfsarKeshmiri, Hessam Oddin Salarian

9120 ------

9122 Modeling and evaluation of hybrid solar driven ejector-compression refrigeration system Mehdi Kalantarian ,Amir Hossein Shiravi, Mohammad Reza Assari

4108 The Effect of Carbon Nanotubes-Water Nanofluid on the Pressure Drop and Laminar Flow Heat Transfer Coefficient under Constant Heat Flux in a Circular Tube Ebrahim Hosseinipour, Saeed ZeinaliHeris, Mehdi Shanbedi, Mojtaba Hosseinzadeh

7128 Investigation of influence of magnetic field on friction factor and Laminar Heat Transfer in a circular tube with Fe3O4-water Nanofluid Mojtaba Hosseinzadeh, Saeed ZeinaliHeris, Ebrahim Hosseinipour, Mehdi Shanbedi

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Poster Session Thursday, June 13

10:30-11:00

Paper No.

Title

4117 Study of energy saving potential in a combined air cooled refrigeration system with evaporative cooling pad Mohammad Ansari, Majid Bazargan, Mehran Ershadifar, Abdul Jabbar Gargash

4119 Experimental study on the effect of flat and parabolic mirrors on performance of solar cooker a Iman Mortezaei,Majid Gholinejad, Malek Khalouei

5108 Comparative Assessment of Heat Pumps Performance using Natural and Synthetic Refrigerants Mostafa Mafi,Morteza Shomali, Farhad Sotoodeh

6120 Investigation of Comfort Conditions and Numerical Simulation of Ventilation Systems in Side-Platform Stations Seyyed Hamed Adibi, Moharram Jafari

7101 Numerical investigation into the effect of walls materials and insulations in heat transfer of the conventional walls Hadi Ramin, Pedram Hanafizadeh

7104 HVACsystem modelingbyartificial neural networksin order to achievecomfortand minimizingenergy consumptiona Fatemeh Tavana, seyed Hosein Sadati

7112 -------

7113 Determining the optimal height of the rooftop air-cooled condenser sunshade by Using of numerical simulations and experiments for Boushehr city Mohammad Reza Daneshgar,NavidLatifian, AbdollahAvara, EhsanDaneshgar

7114 A comparison of energy consumption of geothermal heat pump and ventilation system with variable refrigerant in climate of Ramsar Jalal Mirkazemi, Hesam Aldin Salaryan

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Workshop Details

Tuesday, June 10

No. Title Presentor Time Room

1 New technologies in burners Ayub Aadely 14-16 Soroush

2 Flow rate measurement and its applications in HVAC Farzad Jafar Kazemi 14-16 Arash

3 Comparison the efficiency of scroll and screw compressors at lower tonnage and its impact

on reducing energy consumption and cost Biju Kannan 16:30-18 Arash

4 Introduction of new technologies and

improving safety of gas fuel products in residential applications

Hamidreza Ghareie 16:30-18 Soroush

5 An introduction of geothermal heat pump

system and comparing with conventional air conditioning system

Behrouz Amamiyan 16:30-18 Golshan

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Workshop Details Wednesday, June 11


1 Introduction to the fundamentals of air distribution methods Mahdi Danesh 8:30-10 Soroush

2 Introduction and orientation to energy modeling for building by using Design

Builder software Mehran Saadati Nasab 8:30-10 Arash

3 Practical approaches in designing and selecting of air-cooling systems

Seyed Ali Tatatabaie pour 11-12.45 Arash

4 Proper implementation of infrastructural systems and their role in the comfort of

residents and building quality Vahid Dousti 11-12.45 Soroush

5 Introduction of VRP Systems Mohammad Ali Akhlaghi 16:30-18 Soroush

6 Problems in cooling data centers Zare Anjargholi 14-16 Arash

Workshop Details Thursday, June 12


1 Fundamentals of technical examination of mechanical installation room Soheila Khoshnevisan 8:30-10 Arash

2 Designing of Metroventilation Systems Reza Madahiyan 8:30-10 Soroush

3 Introduction to sub-metering of energy in buildings Arash Aharpour 8:30-10 Tosan

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New Design Criteria in HVAC&R

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Present a new approach to reduce the risk of condensation in radiant cooling system in different climates of Iran

Navid Morovat1, Mehdi Maerefat2

1- Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran. 2- Department of Mechanical Engineering, Tarbiat Modares University, Tehran, Iran

* P.O.B. 14115-111 Tehran, Iran, [email protected]

ABSTRACT

In general there are two approaches in the design of HVAC systems: The traditional is given approach in which the supply of heating and cooling load of the building and The approach taken in its design and provide thermal comfort model based on thermal comfort conditions for the occupants are concerned. On the other hand the HVAC systems are classified into two categories: convection and radiation systems. Creating a natural convection or forced convection to providing thermal comfort conditions, as well as providing clean air charge and thus the quality of hold air in a satisfactory condition ambient. In contrast, the radiant cooling system by providing extensive radiation into the environment through radiation heat transfer mechanism has a good thermal capacity. Radiant cooling system and stratum ventilation system including air conditioning systems, are The mechanism of heat transfer and radiation, respectively, have been studied in this research. Because of radiant cooling systems provide thermal comfort and low energy consumption, special attention is nowadays to this systems. These systems are composed of panels with metallic surfaces that are installed on the roof and cold water pipes located inside the panels. The ceiling cooling panels creating an environment to attract large scale and small temperature differential thermal loads through radiation and transfers it to the environment. Condensation of water vapor on the surface of the radiant cooling panel is the limiting factor to the development of these systems. Therefore provide an application solution with low energy consumption is essential in order to solve this problem. In the present investigation, hybrid system of hydronic radiant cooling and stratum ventilation as a new approach and applicable has been introduced. Estimate the condensation in five different climates of Iran include of Tabriz cold climate of Tabriz, temperate climate of Tehran, dry and hot climate of Yazd and temperate, humid climates of Rasht and hot and humid climate of Bandar Abbas for three month of summer for hourly has been studied and analyzed. The results show that use the proposed hybrid system besides providing proper thermal comfort conditions, cause to avoid the condensation in cold climate of Tabriz, temperate climate of, dry and hot climate of and temperate and humid climates, and in the hot and humid climate using the dehumidifier system is necessary in order to avoid moisture condensation risk. Keywords: Risk of condensation, radiant cooling, Stratum ventilation, Energy plus, Climate of iran Industrial/Professional Applications

• The results of this investigation show that the the use of proposed hybrid system, prevent the risk of condensation in hot and humid climate

• Proposed hybrid system providing proper thermal comfort and air quality in different climate of iran.

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Numerical Investigation of thermal performance of optimum Trombe wall

Mehran Rabani1, Vali Kalantar2, Ahmadreza K.Faghih3, Aliakbar Dehghan4

1Ph.D. student, Yazd university; [email protected] 2Assistant Professor, Yazd university; [email protected]

3Assistant Professor, Yazd university; [email protected] 4Associate Professor, Yazd university; [email protected]

ABSTRACT In this paper, the thermal performance of optimum Trombe wall in the 3D dimensional and unsteady state investigated numerically in Yazd, Iran for 6 November, 6 December, 5 January and 4 February. The optimum Trombe wall not only occupies less interior room but also requires less cost to implement. In this study the effect of optimum Trombe wall on the temperature and velocity distributions of interior room were investigated and the results were compared with air conditioning standards. The results show that the ability of optimum Trombe wall to heat the room is the same as that of ordinary Trombe wall. The temperature inside the room is between 20-25◦C, which is similar to the air conditioning standards. Furthermore, velocities are between 0.1-0.4m/s that are desirable for establishment of the flow inside the room and natural convection. Keywords: Optimum Trombe wall, Unsteady state, Natural convection

Industrial/Professional Applications

• Use of the solar heating system of the Trombe wall in the areas with high heat flux (Yazd, Iran) is one of the most effective applications of residential space heating.

• Use of the optimum Trombe wall system reduces the power consumption and the enforcement costs of Trombe wall.

• Solar heating is without any noise and it is suitable for quiet environments such as hotels, Educational places, and residential spaces due to its passive performance.

• Depreciation of the system is low and its maintenance costs are low and affordable.

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Investigation of Combined Heat and Power Generators into Residential Buildings based Polymer Exchange Membrane Fuel Cell

Ebrahim Afshari1, Hossein Motaharpoor2

1Faculty of Engineering, Department of Mechanical Engineering, University of Isfahan, [email protected]

2 Department of Mechanical Engineering, Isfahan University of Technology, [email protected]

ABSTRACT

Heating and power generation (CHP) systems have the potential to make better use of fuels than other technologies, because of their ability to increase the overall thermal energy efficiency upper than 90%. Feasibility of CHP systems is generally driven by economical savings. In addition, economic evaluation of CHP systems is based on site energy use and cost, which could lead to misleading conclusions about energy savings. Since energy savings from CHP systems only occur in primary energy, the objective of this investigation is to demonstrate that feasibility of CHP systems should be performed based on primary energy savings followed by economic considerations. Fuel cell based MCHP is very attractive because of their high electrical efficiency and low emissions of air pollutants. The polymer electrode membrane fuel cell (PEMFC) is especially appropriate for distributed power generation applications, because it can be operated at relatively low temperatures and has any consumptive or motive part. In this paper, feasibility of MCHP based on PEMFC with hourly load analyses for residential application in Isfahan city of Iran analyzed and scrutinizes its effect on annual consumption economies and energies for users, government and environment. One building in Isfahan with about 130 m2 infrastructure selected for the case study, and amount of electric and heat base require energy that used with people in the building estimated with state statistics, and energy requires for heating and cooling the building calculated with Energy plus software in hourly analyses. Cost of used fuels depends on the pervious part, calculated with state energy price and shown using of PEMFC in this building caused annual energy price of building and consuming primary energy decreased.

Keywords: Heating and power generation, polymer electrode membrane fuel cell, building application

Industrial/Professional Applications • High potential of heating and power generation (CHP) systems based fuel cell, because of

their ability to increase the thermal energy efficiency upper than 90%. • Combined heat and power generators based fuel cell systems have the potential to reduce

energy consumption and greenhouse gas emissions of residential buildings. • The CHP systems based fuel cell offer the highest integrated performance.

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Validation of air zonal method for thermal analysis of a building with a double skin facade

Mohammad Reza Daneshgar1,Navid Latifian2, Abdollah Avara3 , Ehsan Daneshgar4

1Mechanical Engineering, Persian Gulf university, Boushehr, Iran ;[email protected]

2Mechanical Engineering, Persian Gulf university, Boushehr, Iran ; [email protected] 3 Faculty Member of Persian Gulf University of Boushehr and member of Construction Engineering

Organization of Boushehr province; [email protected] 4Mechanical Engineering, Chamran university, Ahvaz, Iran ; [email protected]

ABSTRACT

Glass facades, commonly are used in long commercial buildings. As glass facade has a high heat transfer coefficient, heating and cooling load increases. In recent years, the double skin facades are heavily used. The facade is composed of two separate layers, called double skin facade. In the cold season, the air is trapped in the two-shelled can warm the buildings due to the greenhouse phenomenon and in the warm season, with opening inlet valve and outlet air, Due to natural convection, there is a flow of air in double skin facade that helps cooling. Also, this type of facades is used in noisy places as a sound insulation. In this study, for the thermal analysis of the two-shelled scene (DSF) and determination of the velocity and temperature distribution, the relationships between air zonal methods used. In this method, for calculation of the two-shelled air mass flow rate, temperature at each node is calculated. Finally, in accordance with Reliable references, the maximum heating and cooling load calculation error is approximated 15 % compared with results of other methods and Softwares is acceptable. Keywords: validation of air zonal method, Double skin facade, Heating and cooling load.


• In this study, the air zonal approach were used to thermal analysis of a sample building with a double skin facade. • in the analysis of double skin facade, The maximum error of the air zonal method for heating and cooling load calculation is 15%. • Double skin facade, can be used in industrial and constructive HVAC systems to reduce electrical energy consumption from heating and cooling load.

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Check silencer and air systems provide two new optimized designs with software Fluent

Mohamma morad sheyki1, meysam kheyri amnab2*

1 Assistant Professor , Teacher Training University, Tehran martyr Rajai ; [email protected] 2 student at Azad University Aligoodarz ; [email protected]

ABSTRACT One of the fundamental discussions in creation and expansion of metro networks is the issue of providing a fine ventilation system for tunnels and stations of metro. Generally, the fans by sending the air current in the provided channels, take upon the main responsibility in tunnel ventilation. Although researches in direction of reducing sound pollution in metro system is being speedily done, but because of the ever increasing of sound attractive production and creation of synthetic methods, it seems that there is always a need about new researches in this field. Hence, one of the main goals of the study is to attempt for indigenous knowledge in the field. In addition, different climate, different environmental conditions, has led to many proposed methods do not work if circumstances change. In addition to research ahead of familiarity with the subject of noise, experimental performance silencers write a blade channel air to the sound systems gauge , speedometer and gauge pressure is measured in order to determine the input parameters to the software .The simulation software FLUENT model by model type other silencers blade and two in front ventilation fan with the volume of material in each of the projects are evaluated. Between pollution to be audio in ventilation channels for optimum design of a new service.

Keywords: metro , silencers , noise, layout , simulation

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mailto:[email protected]


Performance Analysis of CCHP Systems for a Typical Building in Different Atmospheric Conditions of Iran

Ramin Karami , Masihollah Mahmoudpour ,Farzad Najafi

Research Institute of Petroleum Industry (RIPI), Tehran, P.O.Box 14665-137, Iran; [email protected]

Research Institute of Petroleum Industry (RIPI), Tehran, P.O.Box 14665-137, Iran; [email protected] Research Institute of Petroleum Industry (RIPI), Tehran, P.O.Box 14665-137, Iran; [email protected]

ABSTRACT The performance of combined cooling, heating and power (CCHP) systems is obviously dependent on the climate conditions. This paper presents a technical analysis of the CCHP generation systems for a typical building in five different atmospheric conditions. Energy delivered, CO2 emission reduction are considered as important criteria to estimate the performance of CCHP systems for a hypothetical hotel building in five cities in Iran with different climates from the technical and environmental. The comparison results suggest that the CCHP system is generally appropriate for Tehran. Combined cooling, heating and power (CCHP) systems use the waste heat created as a byproduct of power generation to achieve an additional heating or cooling task. In recent years, investigations into different types of CCHP systems due to their importance in saving energy resources and pollution reduction have been increased. In comparison with the separate production of cooling, heating and power, the CCHP systems have higher safety and independent of the public electricity grid. The CCHP system allows an institution (company, plant, hospital, hotel, or business center) to generate its own electric power and use the rejected heat from turbine to run an absorption chiller or a heat recovery boiler to handle the possible heating or the cooling loads. The design and operation of CCHP systems are greatly depend on the seasonal atmospheric conditions, which determine thermal and power demand. Iran is located in the Middle East between latitudes of 25˚ and 39˚ N and longitude of 44˚and 63˚ E. The total area of the country is about 1.6 million km2. The climate is influenced by Iran’s location between the subtropical aridity of the Arabian Desert areas and the subtropical humidity of the eastern Mediterranean area. In most of the areas, summers are warm to hot with virtually continuous sunshine, but high humidity on the southern coastal areas of Persian Gulf and short, cool winter. The application analysis of CCHP systems in different climate zones is advantageous to save energy and decrease greenhouse gas (GHG) successfully in Iran. Generally, multi-criteria investigation for CCHP systems has been paid considerable attention from economic, technical and environmental aspects. The present work aims to analyze the technical, environmental and economic performances of CCHP systems in different climate zones in Iran. The fuel energy consumption model, emission and financial formulation are presented. Finally, the numerical results of a hypothetical hotel building located in five cities are displayed.

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1117

CCHP economic analysis for the hotel buildings in Different Climate zones

Farzad Najafi, Masihollah Mahmoudpour, Ramin Karami, Mohammad Ayazi



ABSTRACT The performance of combined cooling, heating and power (CCHP) systems is obviously dependent on the climate conditions. This paper presents an economic analysis of the CCHP generation systems for a typical building in five different atmospheric conditions. Total annual costs, savings and income are considered as important criteria to estimate the performance of CCHP systems for a hypothetical hotel building in five cities in Iran with different climates from the technical, environmental and economic features. The comparison results suggest that the CCHP system is generally appropriate for Tehran, where from the viewpoint of economic performance, obtains more benefit over other cities. Combined cooling, heating and power (CCHP) systems use the waste heat created as a byproduct of power generation to achieve an additional heating or cooling task. In recent years, investigations into different types of CCHP systems due to their importance in saving energy resources and pollution reduction have been increased. In comparison with the separate production of cooling, heating and power, the CCHP systems have higher safety and independent of the public electricity grid . The CCHP system allows an institution (company, plant, hospital, hotel, or business center) to generate its own electric power and use the rejected heat from turbine to run an absorption chiller or a heat recovery boiler to handle the possible heating or the cooling loads. The design and operation of CCHP systems are greatly depend on the seasonal atmospheric conditions, which determine thermal and power demand 8. Iran is located in the Middle East between latitudes of 25˚ and 39˚ N and longitude of 44˚and 63˚ E. The total area of the country is about 1.6 million km2. The climate is influenced by Iran’s location between the subtropical aridity of the Arabian Desert areas and the subtropical humidity of the eastern Mediterranean area. In most of the areas, summers are warm to hot with virtually continuous sunshine, but high humidity on the southern coastal areas of Persian Gulf and short, cool winter. The application analysis of CCHP systems in different climate zones is advantageous to save energy and decrease greenhouse gas (GHG) successfully in Iran. Generally, multi-criteria investigation for CCHP systems has been paid considerable attention from economic, technical and environmental aspects. The present work aims to analyze the technical, environmental and economic performances of CCHP systems in different climate zones in Iran. The fuel energy consumption model, emission and financial formulation are presented. Finally, the numerical results of a hypothetical hotel building located in five cities are displayed.

Proceedings

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1118

Evaporating heat transfer of R-600a: An experimental study of the major parameters affecting heat-transfer

Saeed Baqeri 1, M.A. Akhavan-Behabadi 2, M. Nasr 3

1M.S Graduate, School of Mechanical Engineering, College of Engineering,University of Tehran,

[email protected] 2Ph.D. Professor ,School of Mechanical Engineering, College of Engineering,University of Tehran,

[email protected] 3 Ph.D Candiade, School of Mechanical Engineering, College of Engineering,University of Tehran,

[email protected]

ABSTRACT In this paper, heat transfer characteristics of the hydrocarbon refrigerant R-600a during flow boiling inside horizontal smooth tube are investigated. For this purpose an experimental set up was constructed The test section was a plain copper tube with outside diameter of 9.52 mm and wall thickness of 0.63 mm. The experimental tests are carried out varying: (i) the refrigerant mass fluxes within the range of 70–350 kg/m2s; (ii) the vapor qualities within the range of 0.1–0.9. The Results indicate that the average flow boiling heat transfer coefficient increased as the mass velocity increased in the fixed vapor quality. Moreover, the heat transfer coefficient increased by the increase of vapor quality as the mass velocity was fixed. Present study experimental data for flow boiling heat transfer coefficient was compared with some existing correlations in order to find out which correlation could predict the convective boiling heat transfer characteristics of HC-R600-a. The results indicate that Gungor–Winterton correlation had the best consistency with present study experimental data for HC-R-600-a refrigerant.

Keywords: Convective boiling, Heat transfer, R-600a, hydrocarbons


• Environmental issues such as ozone depleting and global warming, natural working fluids and

their use in air conditioning, heat pump and refrigeration systems are attracting increasing interest from manufacturers, users and scientific research. Natural refrigerants such as isobutene (R600a) have been studied to replace CFCs, HCFCs and HFCs in refrigeration, air-conditioning and heat pump systems.

• Hydrocarbons have better energy performance comparing with other refrigerant. Thanks to their outstanding thermodynamic characteristics, hydrocarbons make particularly energy-efficient refrigerants.

• The results of this study can be used in the case of designing heat transfer exchangers using hydrocarbon R-600a as the refrigerant for the air-conditioning systems.

• Gungor–Winterton correlation had the best consistency with present study experimental data for HC-R-600-a refrigerant.

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Numerical And Experimental Investigation On The Flow Efficiency In Perforated Dimple-Louvered Fins Banks In Compact Heat Exchangers

H. Shokuhmand, M. Ashjaee, F.Sangtarash

Professor of Mechanical Engineering, University of Tehran, Tehran, Iran, [email protected], School of Mechanical Engineering, University of Tehran, Tehran, Iran, [email protected]

P.H.D Student, University of Tehran, Tehran, Iran, [email protected]

ABSTRACT Numerical and experimental analyses are performed on simple louvered and perforated dimpled-louvered fin bank geometry in low and medium Reynolds regimes to investigate the effects of perforated dimples on flow efficiency which is a good representative of heat transfer rate. In order to properly investigate the flow characteristics, LES method is used to model the low Reynolds turbulence flow. Velocity field is discussed for various Reynolds numbers to obtain flow efficiency. A low turbulence wind tunnel with 460 x 460 mm cross section and 600 mm length for test section has been employed. In different Reynolds numbers the flow efficiency has been calculated numerically and experimentally by flow visualization method and the results show that dimples can increase flow efficiency about 6% in fin banks. For higher Reynolds no this effect is more considerable because of more louver directed flow while in lower Reynolds no duct directed flow decreased this effect. With optimizing the shape and number of dimples and perforations on each louver more flow efficiency and consequently more heat transfer enhancement can be expected that can lead to lower total weight and material consumption of compact heat exchangers. Keywords: Multi-louvered fin, Perforated Dimple, Flow efficiency, Compact heat exchanger.


• Results of the article can be applied for energy audit in industrial HVAC systems. • Results of the article can be applied for Vehicle industries. • This innovation causes lower weight for Radiators and other louver type heat exchangers.

1119

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Flow Boiling Heat Transfer of R-134a inside a Smooth Tube with Different Tube Inclinations

S.G. Mohseni 1, M.A. Akhavan-Behabadi 2

Center of Excellence in Design and Optimization of Energy Systems, School of Mechanical Engineering,

College of Engineering, University of Tehran 1 [email protected], 2 [email protected]

ABSTRACT An experimental investigation has been carried out to study the heat transfer characteristics during evaporation of R-134a inside a single smooth tube. The experimental facility makes the tube capable of having different inclination angles, α, with respect to horizon. The experiments were performed for seven different tube inclinations, α, in a range of -90° to + 90° and four refrigerant mass velocities in a range of 53 to 136 kg/m2s for each tube inclination angle. The experimental results indicate that the tube inclination noticeably influenced the vapor and liquid distribution as well as the evaporation heat transfer coefficient. It was found that for all refrigerant mass velocities, the highest heat transfer coefficient is attained at inclination angle of α = +90°. The effect of tube inclination angle on heat transfer coefficient is more prominent at low vapor quality and mass velocity. A correlation has also been developed to predict the heat transfer coefficient during flow boiling inside a smooth tube with different tube inclinations. Keywords: flow boiling; heat transfer; tube inclination; R-134a

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Heat transfer performance and exergy analysis of corrugated plate heat exchanger using nanofluids

Malek Khalouei1, Majid Gholinejad2, Iman Mortezaee3

1Department of Mechanical Engineering, Azad University of Mashhad, Mashhad, Iran;

[email protected] 2Department of Mechanical Engineering, Ferdowsi University of Mashhad, Iran; [email protected]

3Department of Mechanical Engineering, Ferdowsi University of Mashhad, Iran; [email protected]

ABSTRACT Heat exchangers have been extensively used to improve the heat transfer efficiency from one application to another. Nanofluids are coolants, which can cause better thermal performance in heat exchangers. In this paper the effects of water and CuO/water nanofluids (as coolant) on heat transfer coefficient, heat transfer rate, frictional loss, pressure drop, pumping power and exergy loss in the corrugated plate heat exchanger has been studied. The heat transfer coefficient of CuO/water nanofluids increased about 18.50 to 27.20% compared to water. Also, by applying nanofluids, the heat transfer rate has been improved. On the other hand, exergy dissipation was decreased by 24% using nanofluids comparing to water. Moreever, 34% higher exergetic effective heat transfer was found for 1.5% volume of nanoparticles. So, the performance of plate heat exchanger can be improved by using the working fluid with CuO/water nanofluids. Keywords: corrugated plate Heat Exchanger, nanofluids, heat transfer rate

1125

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Improving hybrid desiccant cooling cycle for tropical areas

Seyed Zia Miri1, Ghassem Heidarinejad2, Hadi Pasdarshahri3

1M.Sc. Student, Faculty of Mechanical Engineering, Tarbiat Modares University; [email protected] 2Professor, Faculty of Mechanical Engineering, Tarbiat Modares University; [email protected]

3Assistant professor, Faculty of Mechanical Engineering, Tarbiat Modares University; [email protected]

ABSTRACT Hybrid desiccant cooling systems provide separate controls for temperature and humidity and the possibility of using evaporative cooling in humid areas. In This paper the performance of a hybrid desiccant cooling cycle has been investigated. After introducing a common desiccant cooling cycle including desiccant wheel, cooling tower, cooling coil and evaporative cooling, a new cycle for increasing cooling capacity and obtaining comfort conditions is proposed. In this new cycle the dehumidifier is used in two stages, and the inlet air to desiccant wheel is pre-cooled by cooling coil. The governing equations to simulate the components of the system are presented and the numerical simulation results are compared with experimental results. The results of the studied cycles show that increasing regeneration temperature causes an increase in saturation efficiency and cooling capacity and it has a greater impact on the proposed cycle. The performance of the common and proposed cycle have also been compared for several cities of Iran. The results show that the proposed cycle provides better thermal comfort conditions and increases cooling capacity substantially. Keywords: Desiccant cooling, Evaporative cooling, Wet cooling tower, Thermal comfort


• The proposed cycle can provide thermal comfort for tropical areas and increase cooling capacity.

• Desiccant systems can control temperature and humidity separately. • Hybrid desiccant cooling reduces energy consumption compared with compression

refrigeration cycles.

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The Role of ASHRAE Estandard to Protect Monuments

Samane Sharif, Mahdiye Sharif, Vahid Esmaieli

?

ABSTRACT The key element in prolonging the lifetime of historical artefacts is to achieve standard environmental conditions for their preservation and conservation. Museum is one the continuous storage areas for such historical artefacts. Despite extensive studies on the standard environmental conditions and advances in ventilation technology, established professional standards for understanding the interplay between preservation conditions and average lifetime of historical artefacts and objects are scarce. Nevertheless, references and resources of the related fields can be used as criteria for comparison. These resources can benefit both conservators and curators. This work tries to study the “ASHRAE” manual in identifying artefact storage conditions, heating, cooling, and ventilating system designs, and suitable storage rooms. In this regard, the conditions of one of the storage rooms in the Bonyad Institute of Cultural Heritage is studied using the said standard. Keywords: ASHRAE standards, Conservation, Artefacts, Museum

2103

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37


Investigation of Energy Consumption and Energy Label in 40 Office Buildings in Tehran

Hasan Naderi Mahabadi1, Farnoush Rezvani2, Farhad Minaee 3, Gholamreza Nasiri 4

1Energy Expert, Khobregan Behinesaz; [email protected]

2 Energy Expert, Khobregan Behinesaz; [email protected] 3Architect, Khobregan Behinesaz; [email protected]

4Energy Expert, Vice-Presidency for Strategic Planning and Supervision; [email protected]

ABSTRACT

Energy is one of the main factors for developing countries and accessibility to energy shows their potential for progress in economy and politic. Need to become more industrialized, increased the costs, investments and consumption of energy. In worldwide, buildings are responsible for over 40 percent of the total primary energy use and related greenhouse emissions. In Iran also buildings are the biggest energy consumers and conserving energy in this section has an impressive effect on environment and reducing energy producing costs. Determination of energy consumption factors in building have an important role in conserving energy which in the present study have been investigated for 40 office buildings in Tehran. For this purpose, surface heat transfer coefficients of walls, windows and roofs are calculated in accordance with Iranian National Building Regulation code. In addition, energy consumptions for equipment, heating, cooling and lightening are measured for one year. Results show that roofs don’t meet standard requirement while windows were able to meet the need. Finally, energy label for all buildings have been calculated through ISIRI 14254 (Institute of Standards and Industrial Research of Iran) and label C was the best energy label in all office buildings. Keywords: Energy audit, Surface Heat Transfer Coefficients, Energy Index, Energy Label.


• Results of the article can be applied for energy audit in buildings • The results in this article will be useful for construction companies in order to have energy

efficient buildings. • Results show the weakness parts of office buildings in energy saving • Energy label investigation in the present study is a new effort to classify office buildings and it

helps to increase the construction of energy efficient buildings.

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Simulation of leakage and its effects on performance of rotary air preheater a

E. Hajidavalloo1, A. Heidari2, M. Shayan3 T. Mahmoudi Parsa4

1Mechanical Engineering Department, Shahid Chamran University, Ahvaz, Iran; [email protected] 2Mechanical Engineering Department, Shahid Chamran University, Ahvaz, Iran; [email protected]

3Metallurgy & Material Engineering Department, Shahid Chamran University, Ahvaz, Iran; [email protected]

4Mechanical Engineering Department, Ramin Power plant, Ahvaz ; [email protected]

ABSTRACT Rotary air preheater, as a heat recovery equipment has significant effect on the recovery of the waste energy. The important effect of the air preheater on the reduction of fuel consumption has motivated many works to improve performance of the air preheater. Leakage is one of the important issues which decrease the heat transfer and flow rate in the system. In this study the rotary air preheater had been simulated using three-dimensional model and porous media assumption. Effects of radial, peripheral and axial leakages were discussed. The simulation is performed by Fluent software, using standard K-ɛ turbulence model. The numerical results have been validated by experimental results taken from Ramin power plant in Ahwaz. The direct effect of different seal clearances on the performance, mass flow rate and leakage were studied and difference between leakages has been discussed. According to this result radial leakage has the main effect on the operation. Mass flow rate of leakage in the cold section is more than hot section but the effect of hot section leakage on the performance is more than cold section due to more energy content of air at hot section. Peripheral leakages exist in the air and flue sections but its amount is more in the air region. The least leakage belongs to the axial leakage which is flow between air and flue interface in the matrix peripheral and it has little effect on performance of preheater. Keywords: Rotary air preheater, CFD, Efficiency, Leakage, Clearance


• Leakage has effected on losing mass flow rate and heat energy. • Radial leakage is the most important leakage. • Cold radial leakage has lost mass flow rate more than others however hot radial with losing

heat energy has more effect on performance. • Peripheral leakage only could effect on heat transfer between fluids and matrix and has no

effect on losing mass flow rate. • Losing mass flow rate happened on axial leakage which is a little effect on performance.

3102

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Economic Performance Analysis of a CHP System Based on Micro Gas Turbine using Lazaretto method

Somayeh Pirkandi1, Abdolreza Hatamlou2, Jamasb Pirkandi 3

1Faculty of Sciences; Islamic Azad University of Khoy; [email protected] 2 Faculty of Sciences; Islamic Azad University of Khoy; [email protected]

3 Faculty of Aerospace Engineering; Malek Ashtar University of Technology; [email protected]

ABSTRACT Micro turbines use small combustion turbines to provide electric power for distributed generation (DG) applications, including combined heat and power. Micro turbines typically have lower electric generation capacities (30 to 500 Kw) and lower pressure ratios (about 4 versus 8 to 10).Micro turbines are promoted as lightweight, compact, low noise/vibration, low emissions, and fuel-flexible compared to competing DG technologies such as internal-combustion-engine generators.The present paper deals with the parametric simulation and economic analysis of a CHP system based on an micro gas turbine to produce combined electricity and heat energy. The compressor pressure ratio and turbine inlet gas temperature have been chosen as design and optimization parameters for the current CHP system. In the present investigation, the Lazaretto model have been applied for estimation of the electricity price and other costs. The results show that the optimal performance of the system is obtained by the compressor pressure ratio in the range of 4 to 6 bar and decreasing of the turbine inlet temperature causes the reduction of the optimal pressure ratio. Also, the economical investigation results confirms that the system electricity price in an optimum case is about 20 to 29 cents. Keywords: CHP system; Micro turbine; Lazaretto model; Efficiency


• Microturbines use small combustion turbines to provide electric power for distributed generation (DG) applications, including combined heat and power (CHP).

• Microturbines typically have lower electric generation capacities (30 to 500 Kw) and lower pressure ratios (about 4 versus 8 to 10).

• Microturbines are promoted as lightweight, compact, low noise/vibration, low emissions, and fuel-flexible compared to competing DG technologies such as internal-combustion-engine generators.

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Optimization of tunnel ventilation by computational fluid dynamic

Sahar Hassanpour1, Mahdi Moghimi2

1Msc Student, Shahid Beheshti University; [email protected]

2Assistant Professor, Shahid Beheshti University; [email protected]

ABSTRACT The objectives of ventilation in road tunnels are to provide drivers and passengers with an adequate supply of oxygen for respiration and to dilute toxic gases emitted from vehicles up to a safe concentrations. In long tunnels, mechanical ventilation systems such as jet fans and exhaust shafts are needed in addition to the piston effect of the moving vehicles to keep the amount of toxic gases within safety limits. The working principle of a jet fan is that a small portion of the air flow is accelerated in the fan and subsequently re-injected into the tunnel current flow transferring the jet momentum and generating a longitudinal flow. A computational study was carried out to show airflow patterns and pollution levels due to emissions from vehicles. The mathematical equations were solved for velocity and mass fraction of pollution using commercial CFD software FLUENT 14.0. The aim of this simulation is to determine the proper position of Jets fan for optimizing tunnel ventilation. This optimization is done by changing the distance between jet fans and ceiling and altering the jet fan pinch angle which is a system, noted in literature as ‘‘Banana Jet fan”. This type of jet fans has different pitch angles. The system presents the inlet and outlet silencers inclined toward the tunnel floor, and forms a pitch angle (Ө) away from the ceiling. Simulated model is a section of tunnel which is 95 meters long. In fact this length is distance between 2 sequential jet fans in main tunnel. Modeled section of tunnel consists of 12 cars with a distance of 3 meters from each other. The cars move in tunnel with a certain velocity. The results of simulations showed that maximum concentration of pollution occurs under the jet fans. By increasing the distance between jet fan and celling and pitch angle, the maximum value of velocity profile of tunnel gets closer to the center of cross section. Also the best position for installing the jet fans in the tunnel is where the ratio of the distance between fans and the ceiling to the diameter of fans is 1.5 and optimal pitch angle value is 4°. In this degree the amount of pollution in tunnel is 6% less than zero pitch angle. Keywords: Tunnel Ventilation, Jet fan, Numerical simulation


• The optimum location can be determined to install air filters. • When the ratio of the distance between fans and the ceiling to the diameter of fans is 1.5 the

amount of pollution is about 9% less than the ratio of 0.5. • By increasing the pitch angle to 4° the amount of pollution gets 6% less than zero pitch angle.

3108

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41


The effect of water with various hardnesses on the performance of heating and cooling piping systems

Asieh Otaredi-Kashani1, Shahram Delfani2

1author affiliation, Building and Housing research center; [email protected] 2 author affiliation, Building and Housing research center; [email protected]

Abstract

In this paper, the water with various hardnesses of 121, 450 and 1356ppm without using of softener and in presence of conventional water softeners (resin , RO and electromagnetic) is used and their effect and performance is evaluated on heating and cooling piping systems. The investigation of amount and type of fouling and corrosion in heating and cooling piping systems in present of water with various hardnesses and mentioned water softeners shows that the best result in heating piping system is concerned to when RO softener is used. In this paper, hardness of raw water was very high(1356ppm), when RO softener was used and its corrosion rate in heating piping system and boiler is equal with corrosion rate of water with hardness of 450ppm when isn’t used softener. Also, the type of corrosion and oxidation is black magnetite ( 32OFe−γ ) that itself is a protective layer that prevents of further corrosion. When this water is used in cooling piping system and cooling tower, a lot of fouling is formed, but corrosion rate is high, because of forming corrosion under fouling. When hardness and TDS of water is high and isn't used any softeners or is used electromagnetic softener for that, rate and amount of corrosion is low In cooling piping system and cooling tower, Because fouling is formed very much and it is uniform without pores that isn't allowed corrosion is formed under it, but itself creates many problems in the piping system. In all cases, results of using of resin softener results show higher corrosion rate with rising slop. Calculation of Prediction by Langelier saturation index and Raznar stability index of water characteristics, also comparison of experimental results with their predictions in this paper shows that Raznar stability index predicts occurrence deposits or corrosion more accurate than Langelier saturation index. Keywords: fouling, corrosion, softeners of resin , RO , electromagnetic.


• In water with high hardness, using of RO softener in heating piping system with 80°C has the

best result for less fouling and corrosion among using of softeners (Ro, resin and electromagnetic) and without using of softener.

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• In water with high hardness, using of electromagnetic softener in cooling piping system include cooling tower has the least corrosion rate among using of softeners (RO, resin and electromagnetic) and without using of softener, because of forming of uniform without pores fouling.

• In water with high hardness, corrosion rate in heating and cooling piping system is the highest when is used resin softener among using of softeners (RO, resin and electromagnetic) and without using of softener.

Proceedings

43


The effect of water softeners of resin , RO and electromagnetic on performance of heating and cooling system

Asieh Otaredi-Kashani1, Shahram Delfani2

1assistant, Building and Housing research center; [email protected]

2 assistant, Building and Housing research center; [email protected]

Abstract

Fouling and corrosion affect in the quality and durability of heating and cooling piping systems. In this paper, the effect and type of fouling and corrosion by water with hardness of 120 ppm, TDS=600 ppm and pH=8.5-9 in cooling and heating piping systems is investigated in 60 days. Here, cooling tower is used in cooling piping system and boiler is used in heating piping system. Also the effect of conventional softeners (resin , RO and electromagnetic) on the water with same properties and then the effect of soft water by these softeners on fouling and corrosion of heating and cooling systems is studied. The best result of water with mentioned properties is concerned to when RO softener is used in both heating and cooling systems. When RO softener is used in piping system of boiler, the corrosion rate is lower than other causes and also reduces with slow slop with the passage of time. Type of corrosion and oxidation is black magnetite ( 32OFe−γ ) that it is a protective layer and protects metal of more corrosion. Also, When RO softner is used in cooling tower, the corrosion rate is lower than other causes and is increasing with slow slop and the type of corrosion is hematite ( 32OFe−α ). The most corrosion rate in both boiler and cooling tower occurs when resin softener is used. When electromagnetic softener is used, the corrosion rate is almost constant in both heating and cooling piping system that it is higher than without softener in the heating piping systems and equal in the cooling piping systems.

Keywords: water softener , RO and electromagnetic.


• Using of RO softener in heating piping system with 80°C has the least corrosion rate among

using of softeners (Ro, resin and electromagnetic) and without using of softener. • Using of RO softener in cooling piping system include cooling tower has the least corrosion

rate among using of softeners (RO, resin and electromagnetic) and without using of softener. • Corrosion rate in heating and cooling piping system is the highest when is used resin softener

among using of softeners (RO, resin and electromagnetic) and without using of softener.

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National Codes and Standards in HVAC&R

Proceedings

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Energy and exergy analysis of cogeneration cooling, heating and power system with the primary drivers of diesel engine

Mohsen Fallah1, Ali Naseri2

1Lecture, Azarbijan Shahid Madani University; [email protected]

2 Mechanical Engineer, Azarbijan Shahid Madani University

ABSTRACT

In this Paper a Cooling, Heating and Power generation system with an initial diesel engine driver has studied for food processing factory with office and residential buildings, around the city of Tabriz. Heating and cooling load calculations are performed precisely with cooling load temperature difference method. Optimum system is designed in order to achieve maximum efficiency, and mass, energy and exergy balances are performed for each of the components and sub-systems. The proposal cogeneration plant consists of three 6-cylinders diesel engine in power generation capacity 1.8 MW and heat capacity 1422.8 KW and 1474.5 KW in winter and summer season in form hot water with water temperature 84.91 ºC and 117 ºC, respectively. The energy efficiency of the plant is computed 71.49% and 72.64% for cold and warm seasons, respectively. The plant exergy efficiency is obtained 40.87% and 41.77% for the warm and cold seasons, respectively. Keywords: co-generation, diesel engine, exergy, efficiency

Industrial/Professional Applications • Optimal use of cogeneration heating, cooling, and power technology, in industrial applications

and office space and residential • Maximum waste heat recovery from diesel engine as the primary driver heating and cooling • Reduce losses and increase efficiency compared to the single power generating system

4106

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Heating, Ventilating and Air-Conditioning(HVAC) Discharge Air Temperature Control using Generalized Predictive Controller(GPC) for improvement of energy efficiency in

buildings

Alireza Adhami1, Fatemeh Doosti2, Amin Farmanbordar3

1M.Sc of Electrical engineering in Control, National Iranian Oil Producing and Distribution Company (NIOPDC);

E-mail: [email protected] 2M.Sc student of Electrical engineering in Control, Boroujerd science and research branch, Islamic Azad

University; E-mail: [email protected]

3Ph.D of Electrical engineering in Control, Boroujerd science and research branch, Islamic Azad University; E-mail: [email protected]

Abstract

In this paper, applying of Generalized Predictive Control strategy to HVAC system will consider and compare as suggested method has desired and better control performance. Dynamic, nonlinear and large systems such as HVAC account important challenges for analysis, modeling and identification. Numerous methods have appeared and developed for solving created problems such as altitude and complexity of real HVAC model, also Discharge Air is parts of HVAC as appear at position of large scale modeling. Solution of GPC is using of estimated model of systems for process future output prediction and minimizing quadratic goal function for construction of control signal and acquiring optimal control signal in each time and generally GPC named to control methods that with model of selected process and minimization of criteria function obtain desired control signals. In this algorithm desired trajectory equal to prediction horizon before determined now should control signal adjust predicted output possible to desired trajectory to near. In this paper will present practical of GPC on HVAC system via simulation. This strategy for systems and plants related to Oil, Gas, Petrochemical, Chemical industries and Paper Manufacturing industries is extendable and operational. Also other processes are in various industries mainly including to with take into account nonlinearities and disturbance. Here necessity using modern and progressive methods such as GPC sense at process control system. HVAC system that presents similar to model of chemical process plants or fluids mixing uses for evaluating action of GPC under various conditions. Simulation with usage of Matlab software for modeled HVAC system control is using GPC that shows practicality of suggested controller. And also will tell that controller could produce special and suitable control signals subject to plant nonlinearities, disturbance and measured noise. As process control system using of fixed controllers that is almost unable to plant control that have variable parameters and applied disturbance to system along process. Practical example and laboratory of HVAC system convert to classic designing of educational equipment of control engineering and could see that at various control laboratories around of world. This strategy for systems and plants related to Oil, Gas, Petrochemical, Chemical industries and Paper Manufacturing industries is extendable and operational. Also other processes are in various industries mainly including to with take into account nonlinearities and disturbance. Results of this research practically have application in NIOPDC. This

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requires to citation that applied numerical example at simulations is selected to similar responses for having real system extendable and usable. Keywords: Discharge Air Temperature, Heating, Ventilating and Air-Conditioning, Generalized Predictive Control, Minimization, Prediction horizon.


• HVAC systems use, in vast of applications such as power stations, oil refineries, petrochemical industries and office, commercial and residential buildings.

• Dynamics controller is necessary for design to afford constraints. Some important applications of suggested controller observe in distillation column, paper producing plant, servo mechanism and armed robot.

• GPC is so attractive control strategy for applying to large scale systems and quick processes therefore in important and various industries such as aerospace and petroleum and petrochemical …use of them.

• HVAC systems of buildings consume large energy therefore usage of suitable control method could so effective in industries to prevent from energy losses.

Proceedings

49


The Effect of Carbon Nanotubes-Water Nanofluid on the Pressure Drop and Laminar Flow Heat Transfer Coefficient under Constant Heat Flux in a Circular Tube

Ebrahim Hosseinipour, Saeed Zeinali Heris, Mehdi Shanbedi, Mojtaba Hosseinzadeh

Department of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran

ABSTRACT

In this study, forced convective heat transfer and pressure drop behavior of carbon nanotubes-water nanofluid were evaluated under constant heat flux in a circular tube. For this purpose, the multi-walled carbon nanotubes (CNT) with a length of 10-20 µm, and an average diameter of 30 nm were used. Then, to obtain a homogeneous suspension of CNT was used from gum Arabic surfactant. CNT-water nanofluid was prepared in the concentration of 0.05%, 0.1% and 0.2%wt. and was evaluated in Reynolds number range of 800-2000. The test section is made from copper tube with an inner diameter of 7 mm, and a length of 1000 mm. Also, all experiments were performed at a constant heat flux of 19.3kW/m2. The results indicate a significant increase in convective heat transfer coefficient of nanofluids with increasing concentrations. However, heat transfer coefficient is enhanced with increasing Reynolds number. The maximum heat transfer coefficient is related to the highest concentration (0.2%wt.) and Reynolds number (2034). Pressure drop data on the different concentrations and Reynolds numbers are also investigated. The results show that the pressure drop of nanofluids is a negligible difference as compared with deionized water. Therefore, CNT-water nanofluid is suitable for use in the practical applications. Keywords: Nanofluid, Carbon nanotubes, Convective heat transfer, Pressure drop


• By looking at the different obstacles of the electronic equipments such as high level of heat production/loading, lack of area for heat-exchangers systems and poor heat transfer with the air, utilizing Carbon nanotubes- nanofluids can be selected as a dominant route to remove the amount of excessive heat which has been produced.

• In order to reduce the volume ration of cycling fluid, size of thermal equipments and enhance the performance of pump, Carbon nanotubes-nanofluids can be employed in the common heat-exchangers in buildings.

• Also, some of the military instruments and equipments require the special coolers which are able to transfer enormous heat ratio. In the most cases, common and basic fluid cannot provide above-mentioned conditions. According to our conclusions, Carbon nanotubes- nanofluids can solve the hardships and facilitate the route with a cost-effective route.

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Making Dimensionless Inlet Variables to Present a General Approach for Analysis Indirect Evaporative Cooling Counter-flow and Cross-Flow Heat Exchangers

Ali Sohani1, Hamidreza Hasani-Baliani2, Hoseyn Sayyaadi3

1, 2Faculty of Mechanical Engineering, KNT University of Technology;

[email protected], [email protected] 3Energy systems Engineering Department, Faculty of Mechanical Engineering, KNT University of Technology ;

[email protected]

Abstract

In this study, first, we represent counter flow and cross flow heat exchangers which are used in dew point indirect evaporative coolers. Then, we regard seven case studies include several commercial and experimental samples. In order to better comparison between numerical results and experimental data, using dimensional analysis, we should make dimensionless the inlet air temperature, inlet velocity, amount of working air and channel length and then evaluate their effects on dew point effectiveness, wet bulb effectiveness and coefficient of performance based on heat exchanger model. In summary, results show that dew point effectiveness, wet bulb effectiveness and coefficient of performance in both of heat exchangers are the same. It was seen that coefficient of performance based on dimensionless the inlet air temperature is linear in both of heat exchangers and increasing in dimensionless the inlet air temperature causes more difference between dry bulb and wet bulb temperature and the supply air can be cooled to lower temperatures, and so, dew point effectiveness and wet bulb effectiveness increase in both of heat exchangers. Also, increasing in dimensionless velocity causes less difference between inlet and outlet air temperatures and so, all the outlet quantities decrease and approach to a defined value. This defined value, relied on dew point effectiveness, is about 0.7 for both of heat exchangers, relied on wet bulb effectiveness is about 0.3 for counter flow heat exchangers and about 1 for cross flow heat exchangers and relied on coefficient of performance, is about 3 for both of heat exchangers. By increasing the ratio of working air to inlet air flow rate, amounts of dew point effectiveness and wet bulb effectiveness increase, but in cause of desired effect of increasing the difference between inlet air temperature and outlet air temperature up to 0.3, the amount of coefficient of performance increases. After this, coefficient of performance decreases in cause of decrease in the supply air flow rate. Also, in this status, maximum amount of coefficient of performance is about 800 in both of heat exchangers. By increasing the dimensionless length, all the outlet quantities will increase and approach to a defined amount. This defined amount, relied on dew point effectiveness is about 0.97 for counter flow heat exchangers and about 0.9 for cross flow heat exchangers. Also, relied on wet bulb effectiveness, this amount is about 1.4 for counter flow heat exchangers and about 1.3 for cross flow heat exchangers and relied on coefficient of performance, it's about 550 for counter flow heat exchangers and about 830 for cross flow heat exchangers

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Keywords: Dew point evaporative cooling, Counter-flow heat exchanger, Cross-flow heat exchanger, Dimensionless parameters, Experimental & Numerical results


• System introduced in this paper, prepare fresh and cold air without increasing humidity and also has dew point effectiveness more than 1.

• Results can be applied for setting appropriate values for inlet parameters. • According to variation of COP with increasing ratio of working air, recommended that the

ratio set around 0.3.

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Sensitive analysis of dual expander C1/N2 and single mixed refrigerant processes to feed gas compositions changes in small-scale LNG plants

Amirhosein Moradi1, Mostafa Mafi 2, Mansor Khanaki3

1 M.S Student of mechanical engineering, Imam Khomeini International University; [email protected] 2 Assistant Professor of mechanical engineering, Imam Khomeini International University; [email protected] 3 Assistant Professor of mechanical engineering, Imam Khomeini International University; [email protected]

ABSTRACT

There are a wide range of liquefaction processes based on cascade, mixed or pure refrigerant cycles depending on the size and application. Dual expander nitrogen and single mixed refrigerant processes are the most proposed solution suitable for small-scale LNG plants. In comparative assessment of suitable processes for small-scale plants, in addition to the power requirement, the sensitivity of processes to feed gas compositions changes shall be taken into consideration. In this paper, dual expander C1/N2 and mixed refrigerant processes have been investigated. The results indicate that the expander process is less sensitive to feed gas composition changes regarding to the mixed refrigerant process. Keywords: LNG plant, peak-shaving, sensitive analysis, dual expander C1/N2 process, mixed refrigerant process


• The expander processes are prior to mixed refrigerant processes in peak-shaving LNG plants due to the less sensitive to feed gas compositions change.

• In comparative assessment of suitable processes for small-scale plants, in addition to the power requirement, the sensitivity of process to feed gas compositions changes shall be taken into consideration.

• The efficiency of expansion devices in expander processes is a key parameter in liquefied natural gas production rate.

4113

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53




Prediction of Thermodynamic Properties of Gas-Helium from 10 to 1500 K and at Pressures up to 100 MPa using fundamental equations of state

Mohammad Maboudi1,Masoud Ziabasharhagh2

1M.S. Student of mechanical engineering, K. N.Toosi University of Technology;

[email protected] 2Associate professor of mechanical engineering, K. N.Toosi University of Technology; [email protected]

Abstract

The prediction of very low temperatures processes, known as cryogenics, is one of the significant processes in science and industry. For this purpose it is necessary to know the thermodynamic properties of cryogenic refrigerants. Moreover although there are various thermodynamic-property tables and graphs, in designing the refrigeration systems, the thermodynamic properties need to be exactly estimated by the computer which, in turn, is in need of special formulation such as equation of state. In this paper, at first, various types of equation of state have been presented and their weaknesses and strengths have been assessed in comparison with the fundamental equation of state. Despite the fact that the fundamental equation of state is more complicated than other equations, it is more accurate. Furthermore, its main advantage is that all of the thermodynamic properties can be obtained by differentiating it. Next the equations required for predicting the thermodynamic properties of helium have been presented, using the fundamental equation of state. Then, a computational code was developed for calculating the thermodynamic properties of helium from 10 to 1500 K and at various pressures up to 100 MPa. Finally, making a comparison between the result obtained and valid experimental data showed that fundamental equation of state benefit from high accuracy. Keywords:fundamental equation of state, thermodynamic properties, helium.


• A more accurate fundamental equation of state can be used instead of other equations for predicting thermodynamic properties of materials.

• Fundamental equations of state can be used as a good formulation in computer programs for the thermodynamic property calculation.

• Results obtained for the thermodynamic properties of helium can be applied for simulating refrigerant systems and other industrial application which use helium.

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Study of energy saving potential in a combined air cooled refrigeration system with evaporative cooling pad

Mohammad Ansari, Majid Bazargan, Mehran Ershadifar, Abdul Jabbar Gargash

1Department of Mechanical Engineering K. N. Toosi University of Technology, Tehran 1999143344, Iran [email protected], [email protected]

2Solar cell co. [email protected]

ABSTRACT

Evaporative cooling pad could be used to precondition the entering ambient air to the air cooled refrigeration system. Warm ambient air passes through the wet cooling pad, as a result, the air dry bulb temperature drops near the wet bulb temperature of the ambient air. Humid and reduced temperature air then introduces to the air cooled condenser of the refrigeration system. As the temperature of the air flow reduces on the air cooled condenser, saturated discharge temperature of the refrigeration system reduces to account the bigger temperature difference in the condenser. When the saturated discharge temperature reduces, the refrigeration system will provide more cooling with a reduction of power consumption. On the other hand by using combination of air cooled refrigeration system with evaporative cooling pad, the coefficient of the performance of the system improves. Use of this invention enhances thermo dynamical performance, reduces maintenance cost and refrigeration system lifetime of the system will be longer. In this study the performance of the combined system of air cooled air conditioner and the evaporative cooling pad was experimentally investigated. Energy saving potential of such a system was especially analyzed. Thermo dynamical modeling of the refrigeration cycle performed in order to measure the long term performance of the proposed system. From experimental results, it was found that in certain working conditions, the coefficient of performance in the refrigeration system around 33% improved. The response time of the cooling unit enhanced. Due to the low initial investment and minute maintenance costs for the cooling pad and corresponding accessories, the combined unit is economically competitive. In summary, application of the proposed equipment will provide better thermal comfort, saves electrical energy and as a result the cooling unit will be more environments friendly.

Keywords: evaporative cooling, air conditioning, vapor compression cycle


• The combined cooling unit saves around 30 percent in electrical energy. • At the same nominal refrigeration capacity, the combined unit provides higher cooling effect. • Application of the proposed unit decrease condenser leaving air temperature, which could be

desirable in certain circumstances. • In addition of the thermal operation in the cooling pad, it works as a noise absorber.

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Experimental study on the effect of flat and parabolic mirrors on performance of solar cooker

Iman Mortezaei1, Majid Gholinejad2, Malek Khalouei3

1Department of Mechanical Engineering, Ferdowsi University of Mashhad, Iran; [email protected]

2Department of Mechanical Engineering, Ferdowsi University of Mashhad, Iran; [email protected] 3Department of Mechanical Engineering, Azad University of Mashhad, Mashhad, Iran;

[email protected]

Abstract

To examine the effects of various components of a solar cooker on the performance of this types of cookers, in this paper two similar solar cookers have been built and tested. Solar cookers have three main parts of parabolic mirrors including flat mirrors on the sides and above the solar cooker. In this paper, the effect of removing the mirrors on the solar cooker has been studied experimentally. During the experiments, the mirrors arrangement in one of the systems had not changed and in the other system had changed. To evaluate the performance of solar cooker, input solar radiation to the effective area of the solar cooker has been taken as input energy and the internal energy that changes the water temperature as output energy. The results of the experiments show that the removal of the parabolic mirrors reduces temperature changes over time by 24% and the removal of the two sides of flat mirrors reduces temperature changes over time by 15% and the removal of the above flat mirrors reduces temperature changes over time by 14%. This paper tests has been designed in the Institute of Food Science and Technology, located in Mashhad with Latitude 54 and 36 degrees longitude and 985 meter above sea level. Keywords: solar energy - solar cooker- parabolic mirror- flat mirror

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Design and 3D Simulation of Tabriz Subway Ventilation Systems With Investigation of The Effect Air Washer

Seyyed Hamed Adibi1, Moharram Jafari2

1M.Sc Student, School of Mechanical Engineering, University of Tabriz, Tabriz, Iran, [email protected] 2Assistant Professor, School of Mechanical Engineering, University of Tabriz, Tabriz, Iran,

[email protected]

ABSTRACT

With the industrialization of metropolises, optimization of energy usage and reduction in consumption costs have become the targets of the large industrial companies. In underground transportation systems, the ventilation of subway line is one of the most energy consuming sectors. In this study, the ventilation system of Tabriz subway is designed and investigated by considering energy consumption. Therefore, the ventilation systems of subway is designed based on two methods (with and without air washer). To ensure suitability of design and satisfaction of comfort condition, the ventilation system in both methods are simulated. Numerical simulations are based on finite volume methods and k ε− realisable turbulence model. The simulation results show that both types of designed ventilation systems will provide comfort conditions. The results indicate that in the absence of air washer, power consumption of ventilation fans will increase about 27%. It should be noted that against the increase in fan power consumption, high cost of maintenance and equipment of air washer will be decreased. Keywords: 3D Simulation, Subway Stations, Air Washer, Power Consumption


• Nowadays, numerical simulation seems to be necessary to verify the accuracy of the design.

3D simulation plays an essential role in the optimization of designed systems. • The results of this study indicate that in the cities with mild climates, usage of the air washer

in ventilation system are not mandatory. • The results indicate that in the absence of air washer, power consumption of ventilation fans

will increase about 27%. It should be noted that against the increase in fan power consumption, high cost of maintenance and equipment of air washer will be decreased.

4123

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57


Experimental and numerical investigation of thermal storage in a rectangular enclosure filled with phase changed material

Hossein Shokouhamnd1, Babak Kamkari2, Ramin Karami3 , Farshad Kowsary4, Mohammad Ali Akhavan-Behabadi5

1Professor of Mechanical Engineering, College of Engineering, University of Tehran; ([email protected])

2Ph.D. Student of Mechanical Engineering, College of Engineering, University of Tehran; ([email protected]) 3M.S. of Mechanical Engineering, Energy Research Center, Research Institute of Petroleum Industry;

([email protected]) 4Professor of Mechanical Engineering, College of Engineering, University of Tehran; ([email protected]) 5Professor of Mechanical Engineering, College of Engineering, University of Tehran; ([email protected])

Abstract

This paper presents an experimental and numerical effort to investigate the latent heat thermal storage in a rectangular enclosure filled with phase change material. The enclosure was made of transparent Plexiglass to enable the visual observation of the melting process. The right wall of the enclosure was made of a constant temperature heat exchanger while the other walls were insulated. The material used for thermal storage was lauric acid. Thermophysical properties of lauric acid were measured and concluded that it has a great potential for usage in medium-temperature thermal storage units. Experiments were performed with different wall temperatures of 55, 60 and 70 oC by circulating the warm water at desired temperature through the heat exchanger. Numerical simulations conducted using the enthalpy-porosity approach with a fixed grid. Photographs together with recorded temperatures are used to calculate the melt fractions and temporal stored heat in the container. Moreover, solid–liquid interface morphology and temperature field are employed to infer dominant heat transfer mechanisms and time dependent flow structures during different stages of the melting process. The shape of the solid-liquid interface revealed the significant role of natural convection on melting process. The melting rate at upper part of the enclosure was faster than the lower part indicating the presence of a circulating current in the liquid phase. The liquid heats up along the hot wall and cools down along the solid-liquid interface. Increasing the wall temperature from 55 to 70 oC decreased the melting time from 535 to 195 min. Also, the total heat stored in the enclosure increased with rising the wall temperature. Stored energy corresponding to wall temperatures of 55 and 70 oC were measured 175 and 195 kJ respectively. The increased value of stored energy with rising the wall temperature was attributed to sensible heat storage by the phase change material since for all wall temperatures the latent heat storage was the same. Results indicate that during the initial stage of melting, heat conduction is the dominant mode of heat transfer, followed by transition from conduction to convection regime and convection dominated heat transfer at later times. Approaching the end of the melting process, bulk temperature of the liquid PCM increased and stratified temperature field appeared at upper part of the enclosure which revealed depression of the convection currents.

Keywords: phase change material; thermal storage; latent heat; natural convection

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Highlights

• Lauric acid was used as a medium temperature thermal storage material. • Lauric acid was mentioned as a potential candidate for solar thermal systems and heat

recovery applications. • Experimental and numerical investigations were performed to study the latent heat thermal

storage process. • The significant role of natural convection current on melting phenomena was revealed. • Stratified temperature layers were detected at upper part of the storage unit.

Proceedings

59


An experimental study of condensed convective flow patterns in the downward U-shaped tubes with different inclinations

Moslem Mozafari 1, M.A. Akhavan-Behabadi 2, M. Jamali Ashtiani 3

1M.S Graduate, School of Mechanical Engineering, College of Engineering, University of Tehran,

[email protected] 2Professor ,School of Mechanical Engineering, College of Engineering, University of Tehran, [email protected]

3 Instructor, Building and Housing Research Center, Tehran, Iran, [email protected]

ABSTRACT

In this study, two-phase flow patterns and transition zones of the patterns in the condensation process of the refrigerant R-134a in the U-shaped tubes vertically downwards were experimentally investigated. The tests were conducted with seven different inclination angles (angle between the velocity vector of the refrigerant and the horizontal plane in returned inlet U-shaped tube, the trigonometric -90 to +90) with intervals of 30º, in the range of mass velocities from 52 to 225. According to the experiments, it was found that the angular position of the U-shaped tube has a significant impact on the distribution of the condensed liquid and vapor. Annular flow, quasi-annular, intermittent and wavy Slug/segregated patterns, were observed at the inclination angles -90 and -60.Annular flow, annular-wavy and periodic patterns were observed at inclination angles -30 to +60. In addition, stratified flow and stratified-wavy flow patterns were also observed with zero-degree inclination angle and the slug flow pattern was also seen with inclination angle +30 and +60. Annular flow, annular-wavy, distributed and Slug regimes were also observed with inclination angle +90. In this research, the internal diameter of the tube and the average diameter of the returned bend of the U-shaped tube were 747/7 mm and 55 mm, respectively.

Keywords: Flow pattern, experimental, U-shped tube, inclination

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Experimental study of tube inclination and vapor quality effects on boiling heat transfer coefficient of refrigerant R-134a inside Corrugated coiled Tube

Mehdi Esmailpour 1, M.A. Akhavan-Behabadi 2, M. Jamali Ashtiani 3

1M.S Graduate, School of Mechanical Engineering, College of Engineering, University of Tehran, [email protected]

2Professor ,School of Mechanical Engineering, College of Engineering, University of Tehran, [email protected] 3 Instructor, Building and Housing Research Center, Tehran, Iran, [email protected]

Abstract

In this research, the boiling heat transfer coefficients of refrigerant flow R-134a was experimentally studied inside a corrugated coiled tube with different tube inclination angles toward the horizon, α, to examine one of the increasing boiling heat transfer methods.Devices used in this study are a vapor compression refrigeration system equipped to all of the required instrumentation. The system includes a test-evaporator using a standard corrugated tube coil made of copper in which the refrigerant flow R-134a is heated by the heating element. In this study, experimental data for placing tube with seven inclination angles and four different refrigerant mass velocities were collected. Data analysis showed that change of the tube slope has a large effect on boiling heat transfer at low mass velocity and it was found that at low mass velocity of refrigerant and low vapor quality, the maximum boiling heat transfer coefficient related to inclination angle α =+ 90◦, approximately 1.62 times the lowest heat transfer coefficient at α = - 90◦. Also, according to the experimental results, a correlation was suggested for the Nusselt number as dimensionless number replacing h, that the correlation predicts 92% of the results in the range of ± 10% .

Keywords: Boiling heat transfer, experimental, corrugated coiled tube, inclination, R-134a.

5107

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Comparative Assessment of Heat Pumps Performance using Natural and Synthetic Refrigerants

Mostafa Mafi1, Morteza Shomali2, Farhad Sotoodeh3

1Assistant professor of mechanical engineering, Imam Khomeini International University; [email protected]

2M.S Student of mechanical engineering, Imam Khomeini International University; [email protected] 3M.S Student of mechanical engineering, Imam Khomeini International University; [email protected]

ABSTRACT

With the increasing importance of environmental issues, the damaging effects of synthetic refrigerants used in cooling and heating compression cycles including the global warming and destruction of ozone layer has been taken into consideration. In the recent decades, due to environmental sustainability, abundance, availability and appropriate thermo-physical properties, natural refrigerants are currently being considered with potential of Substitute refrigerants. In this paper possibilities and problems of using Propylene (R1270), Propane (R290), Isobutane (R600a), Ammonia (R717), CO2 (R744), R407c, R410a, R12, R22 and R134a as working fluids in heat pumps have been investigated. Outdoor design condition is the main variable of study. Thermodynamic performance parameters of the above-mentioned refrigerants' have been calculated and compared with the changes of outdoor design conditions in summer and winter seasons. Finally, due to the good values in the compared parameters, Propylene was introduced as a refrigerant to replace with synthetic refrigerants in heat pump cycles. Keywords: Natural refrigerants, Substitute Refrigerant, Heat pump, Thermodynamic comparison, Outdoor design conditions


• The substitution of synthetic refrigerants with natural refrigerants causes to reduce the harmful effects of synthetic refrigerants, including global warming and the destruction of the ozone layer.

• Natural refrigerants have lower compressor pressure ratio and exhaust temperatures; so they are more economical and safer.

• Natural hydrocarbon refrigerants are inexpensive and available in our country and obviate the needs of country's refrigeration industry to import refrigerants and their essentials.

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Theoretical analysis of natural refrigerants as substitutes in two-stage cascade refrigeration system

Mostafa Mafi1, Morteza Shomali2, Amirhosein Moradi3

1Assistant professor of mechanical engineering, Imam Khomeini International University; [email protected] 2M.S Student of mechanical engineering, Imam Khomeini International University; [email protected]

3M.S Student of mechanical engineering, Imam Khomeini International University; [email protected]

Abstract

In recent decades, environmental issues associated with greenhouse gases and the destruction of the ozone layer has led to extensive efforts to find suitable alternatives for synthetic refrigerants currently done. Due to environmental sustainability, availability, low cost and suitable thermo-physical properties, natural refrigerants have the chance of being introduced to the refrigeration industry in the future. In the process of rapid freezing and storage of frozen foods, because of a large temperature difference between the evaporator and condenser, the use of single stage refrigeration cycle due to a sharp reduction in volumetric efficiency compressor and performance coefficient of system, is not economical. In such cases, two-stage cascade refrigeration system is usually used. In this paper, the coefficient performance of two-stage cascade refrigeration system has been investigated with different pair refrigerants including R407c-R410a, R717-R407c, R717-R410a, R1270-R407c, R1270-R410a, R290-R407c and R290-R410a by varying temperature difference in the cascade condenser of the system. The results show that, due to the existing potentials in refrigeration industry, paired refrigerant R1270-R410a is the most suitable option for the two-stage cascade refrigerant systems. Keywords: Natural Refrigerant, Substitute Refrigerant, cascade refrigeration, coefficient of performance, Intermediate temperature


• The substitution of synthetic refrigerants with natural refrigerants causes to reduce the harmful effects of synthetic refrigerants, including global warming and the destruction of the ozone layer.

• Natural hydrocarbon refrigerants are inexpensive and available in our country and obviate the needs of country's refrigeration industry to import refrigerants and their essentials.

• The use of R1270-R410a paired refrigerant provides the ability to benefit from the properties of the compressor pressure ratio and outlet temperature due to propylene, and suitable coefficient of performance and volumetric refrigeration effect due to R410a.

5109

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63



Evaluation of turbulence models to simulate air flow in a space with near the floor height air distribution

Mohammad Hassan Fatollahzadeh1, Ghassem Heidarinejad2, Hadi Pasdarshahri3

1M.Sc. Student, Faculty of Mechanical Engineering, Tarbiat Modares University;

[email protected] 2Professor, Faculty of Mechanical Engineering, Tarbiat Modares University; [email protected]


ABSTRACT

As the majority of people spend most of their time indoors and often share the same space, knowledge and prediction of the indoor climate conditions is important to optimise the indoor climate for the occupants at the design phase. A gamut of parameters determine the indoor climate and are important for the well-being of the occupant of a room in terms of thermal comfort and indoor air quality (which are among the most important issues in heating, ventilation and air-conditioning in indoor climates). This study has focused on two parameters, namely temperature and velocity. For the determination and prediction of temperature, velocity and indoor air flow pattern, two important tools are available: measurement and simulation (Computational Fluid Dynamics - CFD). Both tools currently however have limitations in accuracy and reliability with which the flow pattern can be determined. In this study a simulation (Computational Fluid Dynamics - CFD) is investigated extensively with Airpak 2.2 CFD software for a space with 5.16m long, 3.6m wide and 2.5m height. One of simulation main advantages over other tools is its ability to simulate a wide range of configurations. The limited availability of validation data currently restricts the reliability of indoor air flow simulation by CFD but the measurement data of this space are available. The measurement data were also used to compare simulation results for different turbulence models (indoor zero equation, zero equation, standard two equation and RNG two equation). By comparing simulation results obtained from different turbulence models (indoor zero equation, zero equation, standard two equation and RNG two equation) with experimental data in some regions of the space, results show that the indoor zero equation turbulence model is an appropriate turbulence model for simulating indoor climates with displacement air distribution. The flow under investigation results from a displacement ventilation system that is suited in an office in which several heat sources are present. In addition of acceptable agreement of flow patterns of the indoor zero equation turbulence model with experimental data, there is a great similarity with experimental flow patterns obtained from the video recording of the smoke visualization in the space.

Keywords: Computational Fluid Dynamics (CFD), Indoor Climates, Turbulence Models, Indoor Zero Equation

Industrial/Professional Applications • One of simulation main advantages over other tools is its ability to simulate a wide range of

configurations.

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• The limited availability of validation data currently restricts the reliability of indoor air flow simulation by CFD.

• Indoor Zero Equation turbulence model is an appropriate turbulence model for indoor air flow simulations.

Proceedings

65


Numerical study on the effect of inlet air flow rate on thermal comfort and indoor air quality in a displacement ventilation system

Mohammad Hassan Fatollahzadeh1, Ghassem Heidarinejad2, Hadi Pasdarshahri3

1M.Sc. Student, Faculty of Mechanical Engineering, Tarbiat Modares University;

[email protected] 2Professor, Faculty of Mechanical Engineering, Tarbiat Modares University; [email protected]


Abstract

The main purpose of HVAC (Heating, Ventilation and Air Conditioning) systems is to provide thermal comfort conditions of occupants. In this study, we investigated the effect of inlet air flow rate on thermal comfort of occupants and indoor air quality in a displacement ventilation system. In displacement ventilation system, relatively cool and clean air is supplied at floor level at a low velocity. Air from the lower part of the room is induced upward by rising convection flows from heat sources in the room and then is removed at ceiling level. The air velocities in the room are very low. A distinct characteristic of displacement ventilation is the vertical temperature and contaminant concentration gradient, with a sharp horizontal interface between the lower relatively clean and fresh air layer and the upper air layer which is relatively warm and contaminated. To this end, we used simulation (Computational Fluid Dynamics - CFD) as our tool. Simulation (Computational Fluid Dynamics - CFD) is investigated extensively with Airpak 2.2 CFD software for a space that is 5.16m long, 3.6m wide and 2.5m height. One of simulation main advantages over other tools is its ability to simulate a wide range of configurations. We used Indoor Zero Equation turbulence model which is an appropriate turbulence model for indoor climates in our simulations. PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied) parameters as two thermal comfort indices have been investigated. In addition temperature gradient in vertical direction as local thermal discomfort index and mean local air age as air quality index have been probed. Based on the results of this study, by increasing the inlet air flow rate in displacement ventilation system up to critical value, thermal comfort indices get better and then they decreases. Also by increasing inlet air flow rate, temperature gradient in vertical direction and indoor air quality increase. Keywords: Thermal Comfort, Inlet Air Flow Rate, PMV-PPD, Mean Local Air Age, Temperature Gradient in Vertical Direction


• By increasing the inlet air flow rate in displacement ventilation system, thermal comfort indices get better up to critical inlet air flow rate and then they decreases.

• By increasing inlet air flow rate in displacement ventilation system, temperature gradient in vertical direction is increased.

• By increasing inlet air flow rate in displacement ventilation system, indoor air quality is increased.

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Impact of LAF system design factors on contaminant removal and thermal comfort in the operating room HVAC system using OpenFOAM

Mojtaba Amiraslanpour, Jafar Ghazanfarian

Department of Mechanical Engineering, University of Zanjan, University Blvd. 45371-38791, Zanjan, Iran.

ABSTRACT

The impact of LAF system design factors on contaminant removal and thermal comfort in the operating room is investigated. A simple operating room with staffs, patient and surgery light is modeled. LAF system is considered on the ceiling with a constant height partial wall surrounding it and air barrier supply grills around them. Fresh air is supplied to the room through LAF and air barrier systems. Then air is exhausted through the exhaust grills located on the bottom parts of the side walls. Computational fluid dynamics method is used to simulate the air pattern and contaminant distribution in the room to assess the ventilation performance. Then predicted mean vote (PMV) is calculated to assess the thermal comfort for persons in the room. Twenty seven simulations are carried out to determine the impact of three main design factors of LAF system area, supply air velocity and air barrier velocity. It is found that generally better performance for ventilation system of medium LAF systems can be obtained by adjusting the supply air velocity to an average value of 0.4 m/s alongside with the full air barrier velocity of about 2 m/s in the room. On the other hand for the same adjustments, it is recommended to use a higher supply air temperature to achieve a better thermal comfort for the patient and staffs. Keywords: LAF system, Operating room, Contaminant removal, Thermal comfort, Clean room.


• Computational fluid dynamics method is proven to be able to predict the airflow patterns and contaminant distribution in operating rooms.

• Adjusting values of LAF system parameters to the values suggested in this article will cause to have a better ventilating performance and thermal comfort in the operating room.

• Usage of air wall barrier alongside with LAF system in the room will decrease the amount of mean contaminant concentration significantly.

6110

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67


Application of Floor Heating System in New Generation Sustainable Green Domes

Taha Khademinejad1, Shahab Rahimzadeh2, Pouyan Talebizadeh3, Hassan Rahimzadeh4

1Department of Mechanical Engineering, Amirkabir University of Technology; Email: [email protected] 2School of Design, Creative industry faculty, Queensland University of Technology; Email:

[email protected] 3Department of Mechanical Engineering, Amirkabir University of Technology; Email:

[email protected] 4Department of Mechanical Engineering, Amirkabir University of Technology; Email: [email protected]

Abstract

One of the most important energy consumers in rural and urban areas are buildings. Therefore, the role of heating and cooling systems is considerable in buildings with high level of energy usage. Floor heating system is a form of central heating system which achieves indoor climate control for thermal comfort using conduction, radiation and convection heat transfer. In the present study, application of floor heating system in a dome shape room is analyzed numerically. Moreover, the obtained results are compared to the floor heating system in an ordinary room with the same volume and 6m×4m×3m dimensions. The required energy to establish thermal comfort for residents in desired rooms is calculated by simulating the velocity and temperature fields. The velocity and temperature distribution as well as the floor temperature are compared in both systems. The primary results showed that in the dome shape room, the required floor temperature for providing thermal comfort condition is less than the ordinary room. However, the total area of the floor is higher in the dome shape room than the ordinary room. Keywords: Dome shape rooms, Floor heating system, Energy consumption, Indoor climate.


• Results of the article can be used as a new architectural concept by considering the energy performance of buildings.

• The new designed dome shape room has the ability to take the place of temporary tents in the case of natural disasters.

• Moreover, these kinds of homes have less material waste in comparison to regular cubic rooms. Which in turn make them cheaper and more environmental friendly.

• Simulations showed that the thermal comfort condition can be easily reached in the newly designed room.

• Dome shape rooms can be easily couple with renewable and sustainable energies by using rain drops, solar and wind energy.

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Thermal and Ventilation Performance of a Typical Office in a Hot Humid Climate

Roonak Daghigh1, Nor Mariah Adam2

1 Department of Mechanical Engineering, University of Kurdistan; [email protected] or [email protected]

2 Department of Mechanical and Manufacturing Engineering University Putra Malaysia ;[email protected]

ABSTRACT

Nowadays, people spend more time at work and there are associations between long working hours, productivity and health risks. Both thermal comfort and air quality have significant effects on optimum work performance. In order to make indoor environment of offices more comfortable and healthy, proper indoor air quality and ventilation is necessary. Hence, there is a need to investigate the factors that influence thermal comfort as well as the indoor air quality that can be tolerated by the occupants of offices. This paper presents our finding pertaining to thermal comfort parameters, air exchange rate (ACH), age of air values and air exchange effectiveness (AEE) in main office of Mechanical and Manufacturing Engineering Department of University Putra (UPM) Malaysia. The tracer gas decay method has been employed during the experimental procedures to determine air exchange rate, age of air and, air exchange effectiveness simultaneously, thermal comfort variables were measured. It was found that the office was thermally comfortable based on ISO 7730, but result of survey revealed that staff found condition to be slightly cool. The results of ventilation study indicate air flow patterns in the occupied zones which approximate “perfect mixing". The local air change effectiveness at location for office was found to be 1.01 and the measured air exchange rate is also indicating that the provision of outside air for ventilation is adequate. Keywords: Experiment, Survey, Tracer decay technique, age of air, Thermal Comfort


• Results of the work showed that office is comfortable with a temperature of 23.6ºC and relative humidity of 50%.

• The information obtained from questionnaires show that the air quality in the office is almost satisfactory.

• It has been observed that by approaching the AEE to 1, implying that the ventilation air is completely mixed.

6113

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69



Numerical Comparison of Airborne Particles Deposition and Dispersion in a Room with Different Heating Systems

Hamidreza Golkarfard

Department of chemical engineering, Bushehr Branch, Islamic Azad University, Bushehr, Iran; [email protected]

Abstract

Nowadays, people spend most of their time in the indoor environment. Therefore, indoor air quality has become more important than ever before. Many studies have been shown the advantage of low-energy heating systems. The adoption of these energy-efficient heating systems still requires the provision of acceptable indoor air quality. In this research, comparison of deposition and dispersion of airborne particles in three different heating systems is investigated numerically by an Eulerian-Lagrangian method. Simulations are performed by using the commercial software, ANSYS FLUENT. The studied heating systems are floor, wall and HT radiator heating systems. In an attempt to provide such data, the deposition of solid particles ranging from 1 to 10 µm is calculated numerically and the main goal is to survey the removal efficiency of these heating systems. The outdoor temperature is considered for the Sweden climate in winter and the Ashrae standard is used for the indoor air design temperature. The model validation is performed through result comparisons with published data from literatures. The numerical results indicate that deposition ratio of particles in wall heating system stands at the first place and over the 95% of the particles deposit during the running time while HT radiator heating system is at the lowest place. Furthermore, the numerical results show that the floor heating system has a higher removal efficiency of particles from the outlet in comparison with other heating systems. The conclusions maybe drawn as follows: 1. Wall heating and floor heating systems are similar in deposition ratio and have the most deposited particles while HT radiator have lower amount of deposition. 2. Surrounding walls has the most proportion of deposited particles in all studied heating systems. 3. Floor heating system has the most amounts of escaped particles among all the studied cases and wall heating one stand at the lowest place. Finally, it is worth mentioning that one of the major parameter which affects the indoor climate condition is resuspension of aerosols from the floor and floor heating system may increase the resuspension of particles. However, in this investigation the resuspension of deposited particles is not considered due to reduction of CFD running time.

Keywords: Heating system, Particle tracking, Deposition

Industrial/Professional Applications • Results of the article can be applied for evaluating HVAC systems. • The results of this research indicates that wall heating system provide the occupants with

better indoor air condition in comparison with other heating systems. • The mentioned CFD modeling and mesh study can be used for further investigation.

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Experimentally analysis of airflow pattern and temperature distribution in heating a room with floor heating and radiator

Mostafa Rahimi1, Mehrzad E’tezadi2

1 Associate Professor, University of Mohaghegh Ardabili, Ardabil, Iran; [email protected] 2Graduate student, University of Mohaghegh Ardabili; [email protected]

ABSTRACT

The different heating systems are used for heating buildings. Floor heating and radiators are among the most common of these systems. Review and understand the pattern of air flow and temperature distribution when using different heating systems can be play an important role in providing thermal comfort conditions. Due to the difficulty of experimental measurements in real scale and analyzing the resulting data, and also due to advancement of computer calculations, more recent studies have been performed with using numerical model. In this studies various aspects of heat transfer has been checked, but given the development of the topic, the research has focused specifically on one or more aspects. In this paper experimentally, survey the airflow pattern and temperature distribution come from use of these two heating systems in heating a test room with dimensions of 2.4×2.4×2.4 m in three dimensions under steady state. Then both of the heating systems in terms of air velocity distribution and the temperature distribution are compared with each other. The results have shown, when using floor heating systems velocity and temperature distribution more uniform compared to the centralized heating (radiators) that can provide better thermal comfort condition for the residents. Keywords: Flow pattern, Temperature distribution, Floor heating, Radiator.

6119

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71


Investigation of Comfort Conditions and Numerical Simulation of Ventilation Systems in Side-Platform Stations

Seyyed Hamed Adibi1, Moharram Jafari2

1M.Sc Student, School of Mechanical Engineering, University of Tabriz, Tabriz, Iran, [email protected]

2Assistant Professor, School of Mechanical Engineering, University of Tabriz, Tabriz, Iran, [email protected]

Abstract

Nowadays the subway lines are particularly important due to high capacity, high safety and absence of emission production. One of the most important parts in the underground transport systems is the properly design of ventilation systems. Normal ventilation system shall be able to create the comfort condition for passengers and staffs of subway lines. The aim of the this study are to investigate and simulate the ventilation systems of Tabriz subway. Therefore the generated thermal loads in the subway lines are calculated and appropriate ventilation systems are designed. After the three-dimensional simulation, the performance of the designed ventilation systems are discussed. It should be noted that the numerical simulation of ventilation systems are done based on the finite volume methods and with Ansys Fluent software. The results indicate that the thermal load caused by braking process has the highest proportion of generated heat in the subway. This heat source produces about 60% of the total generated heat load in Tabriz subway. Also the results of three-dimensional simulations show that the most inappropriate area for passengers are close to the exit stairs of station. In this area the greatest change in temperature and velocity are seen. Keywords: Industrial Ventilation, Numerical Simulation, Comfort Conditions, Subway Lines


• Three-dimensional simulations of the ventilation system show the path of the airflow in the

subway lines. • The results indicate that the thermal load caused by braking process has the highest proportion

of generated heat in the subway. This heat source produces about 60% of the total generated heat load in Tabriz subway.

• The results of three-dimensional simulations show that the most inappropriate area for passengers are close to the exit stairs of station. In this area the greatest change in temperature and velocity are seen.

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Numerical simulation of thermal comfort in a historical building – Case study: Tabatabayi House

Mahya Nazari1, Ghassem Heidarinejad2

MA, Islamic Azad University, [email protected]

Professor, Department of Mechanical Engineering, TarbiatModares University, [email protected]

ABSTRACT

Today's discussion one energy efficiency and move towards the use of non-fossil natural resources in construction of buildings with especial interest in Science, researchers, and even ordinary people. In this regard in recent years the Iran's energy efficiency and the use of natural, non-fossil energy, is considered In past centuries in Iran, along with tasteful architecture and Iranian art, according to the different climates and natural resource sat the appropriate elements of non-fossil energy in thermal comfort, ventilation, etc., have benefited in most studies focusing on analyzing the characteristics of the historic buildings architectural elements. In terms of energy efficiency, the role of elements according to their climate refers to the quality and performance is described. Therefore, to quantify the amount of energy efficiency in various field such as architectural elements, climate, construction materials, building height, type and size and the position of the openings, the thickness of the walls and ceilings and is unknown and generally must be admitted that few studies has been do not quantify software. The overall goal of this research, quantitative assessment of the best in terms of comfort and space in historic building with traditional valuesin hot climate, hot and dry month using appropriate software(Design Builder)And determine the thermal conditions and to identify effective elements for enjoying the climate characteristics of traditional buildings And answers to questions such as the role of architectural elements for energy efficiency to quantify thermal comfort in hot and dry climates warm months in the case study on how much is a historical monument. In this context, given the many historic buildings of antiquity and architectural elements of the Iranian identity Tabatabaei an house in Kashan dried and hot climate and avail ability of information regarding the number of element model selection and evaluation. And the introduced one of the most important factors affecting thawed fare conditions of the building and is affection specified conditions. Based on these results, the basement of the building was in good condition and thermal studies, the funnel area of the building at about4degreesinternal temperature decreases. Data collection and analytical study of how these descriptions are based on the library and field studies.

6121

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73




CFD Study onthe Air-Side Thermohydraulic Performance of Microchannel Heat Exchanger

Ehsan Gholamalizadeh1,Man-Hoe Kim2

1,2School of Mechanical Engineering, Kyungpook National University, Daegu, South Korea, [email protected]/[email protected]

Abstract

This study presents 3-D CFD simulations of multi-louvered fin and flat tube heat exchangers to estimate the air-side heat transfer and pressure drop characteristics with variation of Reynolds numbers. The heat transfer coefficients and friction factors were determined from the simulation results. The distributions of velocity and temperature are illustrated through the air-side louver geometries. The heat transfer and flow friction characteristics of the exchanger are calculated in terms of the Colburn j factor and the Fanning friction f-factor. The results are compared with the experimental data. The results indicate that CFD simulation can be used as an effective tool for understanding the fundamental thermal-hydraulic phenomena and predicting performance of multi-louvered fin and flat tube heat exchangers. Keywords: Compact heat exchanger, Heat transfer, Pressure drop, Computational fluid dynamics

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Numerical investigation into the effect of walls materials and insulations in heat transfer of the conventional walls

Hadi Ramin1, Pedram Hanafizadeh2

1PhD student of mechanical engineering, University of Tehran; [email protected] 2Assistant professor of mechanical engineering, University of Tehran; [email protected]

Abstract

In this paper, numerical investigations of multilayers wall have been conducted for conventional wall’s materials and insulation in Iran. For being accurate in calculation heating and cooling demand, instead of rough estimation of annual degree day method, direct solution of heat transfer equation under the variable boundary condition of outlet temperature has been used. Different position of insulations and combination of wall material and insulations are examined. Time lag and decrement factor, which is widely used in literature, are calculated here, thus comparison of different material and insulation is done, and so is combination of different configuration of wall’s material and insulations. Results shows that concrete wall has lower time lag and higher decrement factor in comparison with aerated brick, which implement that aerated brick has better thermal performance. Keywords: unsteady heat transfer, Time Lag, Decrement factor


• Results of this paper can be applied in exact assessment of heat transfer through the walls. • Time lag and decrement factor help the design of walls based on their functions. • Different walls configurations have been examined and performance of each one has been

compared.

7101

Proceedings

75


Thermodynamic analysis and optimization of a novel ejector- cascade refrigeration cycle

Damoon Aghazadeh Dokandari 1, Seyyed Mohammad Seyyed Mahmoudi 2, Alireza Setayesh Hagh 3

1 National Iranian Oil Company, National Iranian South Oil Company, Ahwaz, Iran; [email protected]

2 Department of Mechanical Engineering, Tabriz University, Tabriz, Iran; [email protected] 3 Department of Mechanical Engineering, Bostan-abad Branch, Islamic Azad University, Bostan-abad, Iran;

[email protected]

ABSTRACT

Throttling process through expansion valves causes a considerable amount of exergy loss so that reducing this loss improves the performance of compressed refrigeration cycle considerably. In the present work, the effect of using an ejector on the performance of a cascade refrigeration cycle is evaluated. It is concluded that the using ejector and selecting R134a as the high temperature circuit refrigerant cause the COP and second law efficiency to increase by approximately 6.5 percent as compared to the conventional cascade cycle with the same cooling capacity. In addition, several refrigerants including R717, R290, R134a, and R123 are examined to reveal the effect of refrigerant type in the high temperature circuit on the cycle performance. It is also found that, at a temperature of more than 255.4 K, for the evaporator of high temperature circuit, the refrigerant combination of R744-R123 results in a better performance as compared to the other combinations. Finally, the cycle performance is optimized with respect to the temperatures of low temperature evaporator, high temperature evaporator, and the ambient from the view points of both the first and second laws of thermodynamics. It is concluded that the COP and the second law efficiency are the highest when R123 is used as the refrigerant at the high temperature circuit. Keywords: Ejector- Cascade Refrigeration Cycle, COP, Second Law Efficiency


• The maximum COP and second law efficiency of the novel ejector-expansion R744-R134a

cascade cycle experienced approximately 6.5 percent increase. • The exergy destruction rate of the novel ejector-expansion cascade cycle around 8 percent

decrease. • It is concluded that the COP and the second law efficiency are the highest when R123 is used

as the refrigerant at the high temperature circuit.

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HVAC system modeling by artificial neural networks in order to achieve comfort and minimizing energy consumption

Fatemeh Tavana1, seyed Hosein Sadati2

Engineer, K. N. Toosi University of TechnologyFaculty of Mechanical Engineering Department of Mechanic and Industry; [email protected]

Professor, University/ K. N. Toosi University of TechnologyFaculty of Mechanical Engineering Department of Mechanic and Industry; [email protected]

Abstract

In this paper, we used artificial neural networks in order to simulate and control HVAC system in optimized way. At first, within these strategy the HVAC system is trained and then, after evaluation, ability of trained network is tested for predicting the future outputs. Instead of these strategies, the heating and cooling state of studied system is simulated with math and Energy balance equations in MATLAB simulator and obtained results is compared with other results which has been gained. The main advantage of artificial neural network in comparison with Math and Energy balance equation is that artificial neural networks accurately cover the uncertainties and nonlinear behavior of HVAC systems because it uses real data in order to simulate the HVAC system. So, the artificial neural networks have the ability to predict future condition of HVAC system and with this prediction it can schedule the on and off time of boilers and air-handling units to reduce energy consumption and bring comfort condition. . Keywords: HVAC control systems, artificial intelligence, artificial neural networks.


• Results of the article can be applied for energy audit in industrial HVAC systems. • New simulation gives more accurate way to describe nonlinearity of HVAC systems . • The new mentioned technology in this article will be increase the use of renewable energy in

HVAC&R.

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Examining the place of indoor air quality in building´s energy label & LEED license

Mohammad Reza Divband1

1 Master of Architecture, Islamic Azad University/ Yazd; [email protected]

ABSTRACT

The high levels of quality and favorable of indoor air and how can we optimize building´s energy consumption? Is one of the requirements of every buildings .It needs references like energy label to compare minimum quantities and qualities in that. This paper has examined this subject in building´s energy label from national obligations of Iran´s building and in LEED license from GBCI organization focusing on the indoor air and at the end has paid attention to convenient know–how for having minimum indoor air at the first step and having indoor air with high quality at the second step. goal of this study can be refer to important points that haven't been taken in to consideration and these points can make this license more reliable across (around) the country. Keywords: Building´s energy label, Optimization design, Indoor air quality, LEED license


• Due to the lack of enforcement of building energy labels in the past year and its

implementation in the coming years will be to consider the case (indoor air quality) causes promoting energy efficiency in buildings. New simulation method reduces the computational time in CFD application.

• Before building energy labels for each building should be undertaken energy audits It is not considered that the energy audit that can be used by organizations involved in assessment and energy audit.

• Much of the design phase is an indoor air quality Issues 14 and 19 of the National Building Regulations and energy savings are dedicated to the subject of air changes None of the amendments required to comply with the subject matter and cannot be joined in a national building regulations to the Iran.

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Determining the optimal height of the rooftop air-cooled condenser sunshade by Using of numerical simulations and experiments for Boushehr city

Mohammad Reza Daneshgar1,Navid Latifian2, Abdollah Avara3 , Ehsan Daneshgar4

1Mechanical Engineering, Persian Gulf university, Boushehr, Iran ;[email protected] 2Mechanical Engineering, Persian Gulf university, Boushehr, Iran ; [email protected]

3 Faculty Member of Persian Gulf University of Boushehr and member of Construction Engineering Organization of Boushehr province; [email protected]

4Mechanical Engineering, Chamran university, Ahvaz, Iran ; [email protected]

Abstract

used Air cooled rooftop condenser in central air conditioning systems are often installed in open spaces, is exposed to sunlight. Installing a proper sunshade can reduce the negative effects of radiation to some extent. It should be noted that in case of poor design sunshades, the sunshades will have a negative effect on the temperature of the coil (temperature of return air toward condenser) and the air mass flow rate. In this paper, the design and optimization of a simple sunshade model has been studied; that can reduce the effects of radiation on the condenser side of the system to provide the required air flow. The proposed Sunshade in this study consists of only one plate at the top. Our aim has been Determination of the optimum height for the installation of this plate by using of numerical and experimental samples in Boushehr. The optimum height of sunshade was proposed between 2-2.5 m. Keywords: Optimization, Rooftop condenser, Numerical solution, Fluent, Experimental samples.


• According to this study, the optimal height of the air-cooled condenser for hot and humid climates should be in the range between 2-2.5 meters. • providing shadow conditions for air-cooled condensers on the optimal height, can reduce the condenser coil temperature until 2 degrees, therefore the higher efficiency of the system can be obtained in hot and humid areas. • The conducted study in this paper can be applied in air conditioning systems of constructions and industrials to reduce electrical energy consumption.

7113

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79


A comparison of energy consumption of geothermal heat pump and ventilation system with variable refrigerant in climate of Ramsar

Jalal Mirkazemi1, Hesam Aldin Salaryan2

1M.Sc., Islamic Azad University Science and Research Ayatollah Amoli Branch; [email protected] 2Prof, Islamic Azad University Noor Branch; [email protected]

ABSTRACT

Geothermal of heat pump and system with variable refrigerant flow are two competitive products in the market of ventilation airing systems. Never the less little studies regarding comparison of these two systems in terms of annual energy consumption and maximum electrical consumption (peak electrical) have been carried out as yet. In the current research comparison of geothermal heat pump and the system with variable refrigerant flow for one administrative building having the gable roof including two set-together units has been studied in the Ramsar. In order to calculate the heating load Energy Plus trading software has been used. Results show that considering the studied territory which includes atmospheric conditions and temperature of Ramsar town's soil as one of the cities possessing the under-ground warm water the system with geothermal of heat source not only saves more energy compared to system with variable refrigerant flow but also performs better from view point of maximum electrical consumption. Keywords: Geothermal of heat pump- Variable refrigerant flow- Energy saving- Maximum electrical consumption


• Geothermal heat pump in addition to deerease of energy consumption and reduction of

electrical consumption in the hours of peak load has a more invariable operation compared to ventilation system with variable refrigerant flow.

• Geothermal heat pump can play a more effective role in the reduction of pressure of the energy lines.

• Geothermal heat pump is placed out of designation point for the fewer hours in the peak load of consumption and this means provision of a better and more favorable air conditioning for consumers.

• Geothermal heat pumps have a better application for the climates with mild conditions.

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Thermodynamic and Thermo Economic Optimization of Combined Cycle Power Plant of Shiraz

Masoud Ziabasharhagh 1, Bahram Ghorbani2, Mohammad Rezaei3

1 Associate Professor; KNToosi University of technology; Tehran, Iran, [email protected] 2 Phd Student; KNToosi University of technology; Tehran, Iran; [email protected]

3 MSc; KNToosi University of technology; Tehran, Iran; [email protected]

Abstract

Combined cycle power plants are the most effective as they not only have a high efficiency and power but also have other advantages like flexibility and quick operationalization. In this paper, the combined cycle power plant of Shiraz, including gas and steam sections, is economically and technologically analyzed and optimized using the EES software. The evaluation criterion in optimization is a function of the total cost, consisting of overheads (thermodynamic costs) and investment cost (economic costs). In this method, the amount of exergy flow in system lines and the amount of exergy destruction in each component of the cycle are determined. Then, with the application of exergy balance cost in each component of the system, exergy cost equation system is worked out, which in turn helps work out the cost of exergy unit in flow lines, the cost of exergy destruction in different components of the system, and other required variables in the analysis of economic exergy.

Keywords: cycle power plants, exergy, economic exergy, optimization

7117

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Evaluation of the Influence of Exterior Façade on the Annual Energy Consumption of Building in Shiraz and Esfehan Climates

Alireza Zolfaghari1, Mehran Saadati-Nasab2, Elaheh Norouzi3

1Assistant Professor, Department of Mechanical Engineering, University of Birjand, Birjand;

[email protected] 2Student, Department of Mechanical Eng., University of Birjand, Birjand; [email protected]

3Student, Department of Mechanical Eng., University of Birjand, Birjand; [email protected]

Abstract

In this research, the effect of using different facade common materials on the energy consumption has been investigated. For this reason, a test room has been simulated by EnergyPlus software under two different climatic conditions: Shiraz and Esfahan. Results indicated that the brick finishing facade has the best performance by 6.5% energy saving and 9.53 MW energy consumption per year in shiraz climate. Also, the painted concrete facade material with 6% energy saving and 9.96 MW annual energy consumption has been suggested for Esfahan climate. Also, results indicated that the façade with maximum solar absorptance (close to one) and 0.6 has the best performance in Esfahan and Shiraz climate respectively. Keywords: building façade, optimization, energy consumption, thermal comfort


• Select the appropriate building façade prior to implementation and taking into consideration

the topic of energy along the beauty could be reduce energy consumption more than 10 percent.

• The use of break façade fitted up with Shiraz climate can be reduce annual energy consumption up to 6.5 percent. For this climate, the façade with 0.6 solar absorptence has been investigated better functioning.

• The use of painted concrete façade fitted up with Esfahan climate can be reduce annual energy consumption up to 6 percent. For this climate, the façade with 1 solar absorptence has been investigated better functioning.

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Simulation and analysis of Stirling engines, to increase efficiency, use of waste heat

Mostafa mahmoodi1,Jamasb pirkandi2, Seyeedahmad ghavami3

1Assis. Prof., MalekeAshtar Univ., [email protected]

2Assis. Prof., MalekeAshtar Univ., [email protected] 3Researcher, Islamic Azad Univ., Karaj., [email protected]

ABSTRACT

The In this paper, numerical solution of beta-type Stirling engine was presented considering its non-ideal regenerator. To this end, the second-order model including thermal and hydraulic losses of regenerator was used and their effect on the output power and efficiency of the engine was obtained. Then, a numerical code was used for calculating geometrical and physical optimum values of regenerator. To confirm the obtained result, the physical and geometrical parameters of the engine made by General Motors Research Laboratories called GPU-3 were used. According to the obtained results, the values of hydraulic and thermal losses in the regenerator were considerable and led to the decrease in the engine power and efficiency by 18% and 14.8%, respectively. Using the obtained results and numerical code, the amounts of porosity, frequency and length of the regenerator were suggested as less than 0.7, 30 to 40 Hz and 24 mm, respectively and a material with high thermal capacity and low conductivity in the optimum physical and geometrical conditions of the engine. Decrease in regenerator matrix porosity led to the increase of power and output efficiency of the Stirling engine. Pressure drop in regenerator decreased with the increase of regenerator porosity. In fact, as the porosity of regenerator increased, resistance of regenerator matrix against the movement of operating gas flow decreased; as a result, its pressure drop decreased. Efficiency and output power of the engine depended on the intensity of its operational frequency. Power and efficiency increased with the increase of frequency. The most optimum amount for the highest power and efficiency was within the range of 30 to 40 Hertz. By observing the results with regard to the effect of increase in regenerator length on the efficiency and output power of the engine, the best length value of 18 to 24 mm was recommended for the most optimum value of efficiency and output power of the engine, The obtained results demonstrated the increase of work loss caused by increasing pressure drop for the higher values of regenerator length. Also the values of thermal losses caused by internal and external conductivity increased with the increase in the regenerator length. Regenerator matrix can be made from different materials. The performance of the engine depended on the materials applied in the regenerator matrix. To increase temperature changes of regenerator and decrease internal losses by thermal conductivity, a material with high thermal capacity and low conductivity should be selected.

Keywords: Stirling engine, Numerical simulation, Adiabatic model, Non-ideal regenerator, Losses

7120

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Stirling engine is one of the ideas which have attracted the attention of many interested researchers in recent years. In physical terms, the Stirling engine is an external combustion engine and can use any kinds of external heat sources (waste heat from industrial machinery, combustion and solar energy) for producing mechanical energy. Recently, researchers have reached good results in designing and using Stirling engines. Stirling technology development for making solar engines which generate the axial power of 10 KW

is one of the most important achievements. Also, the combined heat and power (CHP) generation plan is one of the new ideas which have been commercialized by the generation companies of this technology and are used in power generation bases. At present, new methods of using Stirling methods are studied which include application of Stirling

engines for providing the required power for satellites and using Stirling engines as an alternative for the steam turbines ofnuclear power plants

Proc

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Optimization of Office Building Facades with GPSPSOCCHJ Algorithm

Mona Khatami1, Maria kordjamshidi2, Behrouz MohammadKari3 , Seyedalireza Zolfaghari4

1M.Sc. In Energy and architecture, Ilam University; [email protected] 2Assistant Professor, Faculty of Architecture, Ilam University; [email protected]

3Assistant Professor, Faculty of Architecture, College of Fine Arts, Tehran University; [email protected] 4Assistant Professor, Mechanical Eng. Department, Birjand University; [email protected]

Abstract

The importance of building optimization to prevent energy waste and provide thermal comfort conditions is evident to all. Replace or improve the efficiency of existing buildings windows and the selection of appropriate types of windows and components (type of glass, frame material, being single or double glazing, type of gas in double glasses, window size and proportions, etc.) in buildings under construction are the way to improve thermal performance and lighting. This paper presents a comprehensive analysis to study the balance between day lighting benefits and energy requirements in perimeter office spaces taking into account glazing properties control with window size, climate and orientation in an integrated day lighting and thermal manner. Glazing area and window thermo physical properties were taken as the main variables. The objective function of optimization task is the minimization of cooling, heating and lighting energy consumption. The office building facades optimization was carried out using a combination of EnergyPlus7.2.0 and GenOpt. The energy consumption significantly can change affected by geometric parameters, materials properties and types of glass, orientation and climate. Optimum range of each parameter was calculated in order to minimize annual energy consumption with a hybrid multidimensional optimization algorithm GPSPSOCCHJ. Furthermore, since the annual energy consumption effectively depends on the type of air conditioning system, the optimization process was carried out individually with both evaporative cooling system and Compression cooling system. This method can be used for other selection of the design process like building material, type of the mechanical systems and space geometry due to the climate. The complex interactions of the studied parameters and their impact on the heating, cooling and lighting energy performance revealed interesting results for an office building in Tehran. The results indicated that using the evaporative cooling system compared to compression cooling system is more appropriate and more economical and if office window has been placed in an optimum orientation, glass area can allocate up to 50% of façade. Also Investigations indicated that reflective double glass and low-e double glazed with argon layer glass is appropriate for Tehran office building units and can respectively allocate the maximum level of window area and the minimum of energy consumption. So that using reflective double glass with evaporating cooling system, the window size can be respectively increased to 47, 58, 46 and 46 per cent of total façade area. The quality of windows can also increase Windows surface considerably. Therefore, if single-glazed windows replaced with conventional double glazed glass and low-e double glazed glass; window size can increase respectively to 11% and 17%.

Keywords: Minimize energy consumption, Window size optimization, GPSPSOCCHJ optimization algorithm

7123

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• Using the evaporative cooling system compared to compression cooling system is more appropriate and more economical in Tehran climate.

• If office window has been placed in an optimum orientation, glass area can allocate up to 50% of façade.

• Reflective double glass and low-e double glazed with argon layer glass is Appropriate for Tehran office building units and can respectively allocate the maximum level of window area and the minimum of energy consumption.

• In the same conditions, using the evaporative cooling system, window optimum size in the four main directions can vary of 19% in the South for single-glazed window to 58% in the South for reflective double-glazed window.

• In Compression cooling system by using reflective double glass Due to a very small allotment of visible light transmission and low solar heat gain, window size could rise up to 41% of surface area.

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Analysis and optimization of air flow through a vertical channel under different thermal boundary conditions

Mostafa Rahimi1, Milad Khalafi Solout2

1

Associate Professor, University of Mohaghegh Ardabili, Ardabil, Iran; [email protected] 2Graduate student, University of Mohaghegh Ardabili; [email protected]

ABSTRACT

How to design HVAC systems is contributing factor in optimizing energy consumption in residential and commercial buildings. A method of natural ventilation is the use of buoyancy force. In this study, the inner walls temperature of the vertical channel is significantly higher than the air temperature at an ambient temperature has been given. This temperature difference causes the buoyancy force and the resulting is displacement of air inside a vertical channel. Heater situation on the channel, the intensity and concentration of heat transfer and the geometric parameters of the channel and the heater can be effectively displaced air flow rate, also the optimum conditions were investigated to evaluate the effects of these parameters so in this conditions it can be moved more air flow with minimum heat consumption. Input conditions, velocity and temperature and the hydrostatic pressure environment at environment temperature is assumed constant. Equations of the flow with axial symmetry inside a vertical tube with using of Businex approximation, constant physical properties, constant pressure in the radial direction and stable flow is considered. For this purpose, a numerical analysis has been used to investigate the flow inside a vertical tube. In this code was written to solve this problem, first the energy equation with using of the finite difference method approximated. Then with using of entry cross-section data, tube temperature distribution in the axial cross section of length the pipe has been obtained. With the same approximation in the momentum conservation equation, the distribution of the axial velocity component has been achieved. With using an additional equation which raises mass conservation in each section of pipe implicitly, pressure at new section coincides with the axial velocity component is estimated. Finally, with the help of continuity equation, the radial velocity component is determined. Based on the results of this study focused heat flux at the vertical tube inlet, the flow rate through the tube increases. Whatever the focus of the heat flux away from the start of the pipe and distribution on the smaller surface of end of the pipe mass flow rate is reduced. Also with increasing the length and diameter of the pipe increases flow rate through the tube but the increasing rate decreased with large increase in length and tends to constant value. Keywords: Natural convection, Vertical channel, Buoyancy force

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Importance of Energy Conservation Policies in Building Sector in Iran & other countries With Approach to Energy Subsidies Decline in this sector

A. Moradi

Iranian Fuel Conservation Organization,[email protected]

Abstract

Without implementation of energy conservation measures in building sector, the slope of annual increase in energy value, compare to base year, 2013, in maximum 10 years scenario, is %30-40(without consideration of fluctuation in currencies and international energy carriers prices). So simultaneously implementation of conservation policies with change in the price of energy carriers is necessary. In United State of America, during a 20-years program, %50 decrease in building sector energy consumption is targeted. Turkey and Brazil, during a 10-yaers program, respectively, targeting %2 &%1.3 decrease in energy intensity .According to this survey, in maximum 10 years scenario, for achievement of target laws of country, with annual Gross National Production growth rate of %2.5 and %20-30 of annual increase in energy value, the necessity of annual decrease in amount of energy consumption from %6.5-9.5 is decreasingly changed to %4.5-7. By this energy savings, annually 200000-300000 bRLS revenue for the country accompany with preventing of 40Mton carbon emission is achieved. In Iran, endeavor of %4 - %7 decrease in amount of energy consumption is more than targets of some developing countries like Turkey and Brazil. So, during a 20-yaers program, with %10 of annual increase in energy value and %2-3 of annual decrease in amount of energy consumption, the targets will be fulfilled .By the consideration of subsidized energy price in Iran, Energy Efficiency Programs (EEP) by standard settings and energy labeling accompany with incentives, advertising and control of HVAC facilities importing market with energy efficiency approach is necessary.

Key word: Energy Intensity Energy Consumption amount /Value –Subsidies Targeting- Carbon mission

Industrial /Professional Applications

• Building sector contribution in final energy consumption in Iran is %35that is like some developed country. %60-70 energy consumption in buildings is related to HVAC

• Besides of 19th code of National Building Law, in Iran standard setting of building energy consumption according to Kwh/m 2/year is completely necessary.

• Developed country approach for design and operation of commercial building is Net Zero Energy Building (NZEB ) and new commercial building according to %50 required energy of ASHRAE 2004 or 27% ASHRAE 2009 (90.1 edition) are designed and operated . target until 2020 mentioned that new and existing residential building will be designed and operated, respectively 30% & 25% energy required according to IECC

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• Population growth and welfare promotion in developing countries is accompanied with growth of HVAC facilities in china for one third of population in warm provinces with 38% saving potential ,260 b Kwh electricity accompany with 216 M ton co2 emission decrease during 15 years

• USA targets for building sector (2010-2030) : lighting : %65 saving, water heating : %37 saving ,Heating/cooling: %24 saving ,Building envelope : %34 saving , control systems &sensors : %18 saving , home appliance : %29 saving

Proceedings

89


Investigation of influence of magnetic field on friction factor and Laminar Heat Transfer in a circular tube with Fe3O4-water Nanofluid

Mojtaba Hosseinzadeh, Saeed Zeinali Heris*, Ebrahim Hosseinipour, Mehdi Shanbedi

Department of Chemical Engineering, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran

ABSTRACT

In modern thermal equipments, there is an essential need for new fluids with higher potentials as compared with base ones, since a large amount of heat should be transferred by them. Despite higher viscosity, employing nanofluids as the base fluids in the thermal equipments may present a new route with optimal condition in the field of pumping. Accordingly, numerous researches have been done by scientists about different factors. Several studies have been carried out about the influence of magnetic field as a key parameter on heat transfer. Some of them reported that as the magnetic field used, the quantity of heat transfer increased. In the present study, the influence of magnetic field on the friction factor and laminar heat transfer was investigated. In presence of Fe3O4/water nanofluid, experiments have been done in a circular tube and constant wall heat flux. First, Fe3O4-water nanofluids in the weight concentrations of 0.1% and 0.2% were prepared and then experiments were repeated in the different Reynolds numbers. Here, all of the mentioned experiments were done in a circular tube with length of 100 cm and diameter of 7mm. Results reported that as the Reynolds Number and concentration of nanofluids increased, the Nusselt number increased which was intensified more in the presence of magnetic field. Also, the friction factor as one of the main parameter in the performance of pump has been investigated. Keywords: Nanofluid, Fe3O4, Nusselt number, Friction Factor


• Using of magnetic nanofluids in thermal equipments can be considered as an efficient route to

increase thermal performance. • Meanwhile, there are lots of excuses to confirm that the amount of heat transfer rate increase

in the presence of magnetic field which is suitable for micro channels. • In some thermal equipment such as free heat transfer equipments, there are numerous

problems especially with their sizes. In order to solve their problems, employing magnetic nanofluids plus counter current flows can play a key role.

* Corresponding author email: [email protected],

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Analysis the effect of the green roof on annual energy consumption in Tehran climate

Alireza Zolfaghari1, Mehran Saadati-Nasab2, Elaheh Norouzi3

1Assistant Professor, Department of Mechanical Engineering, University of Birjand, Birjand; [email protected]

2Student, Department of Mechanical Eng., University of Birjand, Birjand; [email protected] 3Student, Department of Mechanical Eng., University of Birjand, Birjand; [email protected]

Abstract

The influencing factors on heat load building is type of roofing and building materials used in the construction of the roof. One of the building's heating load reduction methods is the use of green roof and application of plants on the buildings. In this study, the impact of influential parameters on annual energy consumption based on green roof buildings has been investigated in Tehran climate. Results indicated that energy consumption of building is almost related to vegetation height change has been used in green roof. So that the use of vegetation with a height of 10 cm can be reduce cooling energy consumption to 23 percent per year. In addition, the results related to changes in soil depth on the roof has been investigated that increasing of the soil depth used in green roof caused decreasing of energy consumption. Keywords: green roof, optimization, vegetation, energy consumption


• The use of plants with a height of 10 cm could be reduce cooling energy of building in an

average 23 percent while the maximum rate of reduction in consumption with 45 percent occurred in May.

• Plants with a height of 10 cm decrease heating energy consumption up to 2 percent. • The depth of the soil where the plants are to be planted is less, energy saving will be more. So

that the thickness of the soil for Tehran climate in 10 cm could be reduce energy consumption about 30 percent in average.

• Select the appropriate vegetation along with optimum soil thickness for every climate and specifically for Tehran could be reduce annual building energy consumption more than 40 percent.

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Courtyard geometry optimization in different climatic region of Iran

Zobeideh bayat1, Jamal khodakarami2, Nazanin nasrollahi3

1M.Sc. in energy and architecture, Faculty of Architecture, Ilam university ; [email protected] 2 assistant professor, Faculty of Architecture, Ilam university ; [email protected] 3 assistant professor, Faculty of Architecture, Ilam university; [email protected]

ABSTRACT

Heating and cooling usually use largest portion of energy consumption of buildings. Therefore, builders tried to use natural climatic strategies for encountering with harsh conditions .Climate is one of the effective elements in city morphology and Iranian vernacular architecture in different regions of Iran. Using central courtyard (hayate- markazi), in order to create coordination with each climate characteristics, is a sample of the Iranian artists’ and architectures’ innovation. . This method has been very effective in creating comfort in traditional houses which was determined by the climate. Courtyard geometry and proportion, is one of the most important design factors that affect on the climatic design of courtyards. So that it is aimed by proportioning the courtyard internal envelope ensuring adequate solar radiation accessibility in winter for warming up the building and providing sufficient shadows in summer avoiding or reducing the need for cooling. Determining of the optimum proportions of the physical parameters of the courtyard form in different climatic regions of Iran is the most important and the focus of this study. In this paper, after introducing the courtyard houses, different climatic regions of Iran, First, a general typology based on the yard proportions of courtyard houses was presented. Then the average amount of radiation absorbed by the surface of the yard for both summer and winter was calculated using computer simulation called Design builder. Weather data from four cities representative of climatic conditions of cold, temperate, hot-humid, and hot-dry were used. The effect of changing the investigated courtyard’s proportions on the produced shaded and sunlit areas was examined through varying the ratios R1 and R2 indicate the depth and elongation of the yard respectively. Finally, after analyzing the results, a range of proportions according to each climate weather conditions was provided. The results showed that the climatic conditions of the examined locations have a predominant effect on the courtyard performance and consequently on the recommended sets of ratios. It was found that, for the purpose of reducing the cooling load in summer and heating load in winter, deeper courtyard forms were the most preferable in hot and dry and hot humid climate whereas shallow form is suitable in cold and temperate climate. Keywords: climate, courtyards, proportion, shading, sunlit area.


• Results of the article can be applied for conceptual design process of courtyard building in

each climatic region of Iran and a range of ratios were recommended to achieve a reasonable performance in both summer and winter in the examined locations

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• In hot humid climates, courtyard with R1 values of 1 and in a hot dry climate, forms tend to be a slightly shallower as the range of advisable ratios varies between 2 and 3 is proper. The tendency is to have, generally, shallow forms in both temperate and cold climates which have R1value varies between 3 -4 and 4-5 respectively.

• In cold climate, it was observed that horizon courtyard elongation is more desirable to achieve a reasonable performance whereas changing the rectangular courtyard elongation value, in the other climates, would not have a significant effect on the shadows produced on the walls.

Proceedings

93


Energy efficient office building concept for Latvian climate

Anatolijs Borodinecs1,Egils Dzelzitis2, Juris Sorokins3

1Dr.sc.ing, Riga Technical University/Institute of Heat, Gas and Water technology; [email protected] 2Dr.sc.ing, Riga Technical University/Institute of Heat, Gas and Water technology; [email protected]

3M.sc.ing, Riga Technical University/Institute of Heat, Gas and Water technology

ABSTRACT

The aim of the paper is to develop building concept for three storey office building using architectural elements of passive cooling. In order to achieve that it is planned to define three basic elements of the building concept – shape of building, sun movement and sustainability of the building. These parameters will serve as corner stones also further in development of building concept .In addition not only passive cooling elements are considered during concept elaboration process but also passive building basic principles which include building location, window placement on facades, room alignment, building constructions and high comfort level. Dynamic simulation software IESVE is used in order to perform required calculations, and after analyzing obtained results to make conclusions and relevant improvements, in that way providing most beneficial result.

Keywords: passive heating and cooling, simulation, office building, microclimate

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Comprehensive design of a nearly zero energy office building

Farzad Rezvani1, Hasan Naderi2, Farhad Minaie3 , Gholamreza Nasiri4

1Energy Expert, Khobregan-e-Behinesaz; [email protected] 2 Energy Expert, Khobregan-e-Behinesaz; [email protected]

3Architectural Expert, Khobregan-e-Behinesaz; [email protected] 4Building Structural Expert, Vice-Presidency for Strategic Planning and Supervision;

[email protected]

Abstract

Nearly zero energy buildings (NyZEBs) are expected to play an important role in fighting climate change and reducing the energy use of the built environment. Developing Nearly Zero Energy Buildings represents a path toward sustainable communities and is required by international regulations. In this study, a three-storey office building with a useful working area of 989 m2, 60 employees and nearly zero energy consumption is designed. Reduction in energy needs and energy production from in situ renewable resources are the two key elements in the design of buildings with zero or very low energy consumption. For reducing energy needs, passive solar design (using proper thermal mass, building integrated vegetation, optimal orientation, envelope, shading, etc.), high efficient equipment and lighting, heat recovery ventilation (HRV) system and for energy production from in situ renewable resources, thermal collectors (domestic hot water and heating), PV panels, ground heat pump and wind turbines have been used. Heating and domestic hot water energy needs and electricity demands have been calculated as 12219 kWh/year and 43810 kWh/year. The in situ heating and electricity energy production have been calculated 22219 kWh/year and 46570 kWh/year, resulting in 8% less than the electricity energy demand. This building has been integrated with the electricity grid and in some months sells the surplus while in others buys the shortage from grid. Keywords: nearly zero energy building, Renewable energy, Energy recovery, solar passive design


• Constructing of nearly zero energy building in most of climatic parts of Iran is possible and

potential reduction more than 90% in energy consumption will be followed. • The technologies which have been used in a nearly zero energy building can be used

separately in new constructions and reduce energy consumption of a specific part like domestic hot water energy until 100 %.

• Due to the exponential increase in the cost of a zero-energy building, construction of building with very low or nearly zero energy consumption will dramatically decrease the costs.

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95


Photovoltaic- thermal systems and applying them for electric generation and bulding heating

Behrooz mirzaei ziapour1, vahid palideh2, naser yadegari3, Mohsen bagherikhalili4

1ph.d mechanic and faculty member, university of mohaghegh ardabili,ardabil; [email protected]

2graduate student of mechanical engineering, university of mohaghegh ardabili,ardabil; [email protected]



Abstract

In this paper, the performance of integrated photovoltaic solar thermal systems (PVT) with and without fins is assessed, where they are installed on the ceiling. This systems has the ability to generate electricity and produce heat for household consumptions, simultaneusely. In addition, a comparative approach is adopted to examine the performance and efficiency of with fin and without fin. results show that, fins has increased the heat transfer and it has improved the efficiency. The room temperature with and without fins reaches utmost 23 degrees Celsius and 15 degrees Celsius, respectively; therefore fin results in an increase of 8 degrees Celsius. Moreover, electrical efficiency has had an improvement of 0.4 percent with fin due to the better transferring of heat between module and room air. In addition, results show that as the packing factor increases, room air temperature rises too, due to the more heat transferring; although, electrical efficiency decreases, when the temperature of solar cells rises. Packing factor is the fraction of collector surface which is occupied with solar cells. Keywords: photovoltaic- thermal system, PVT, fin, bulding heating, solar energy


• Integrated photovoltaic thermal systems decreases the environmental pollutions because of

using solar energy instead of nonrenewable energies like oil and gas. • Appling fins in integrated photovoltaic thermal systems, results in an increases of 8 degrees

Celsius in temperature and an increases of 0.4 percent in electrical efficiency in comparsion with system without fins. The could be improved in different industrial situations.

• Presented system can be applied in air conditioning systems for factories and produce heat and generate electricity.

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Thermodynamic analysis of a compression-absorption refrigeration system assisted by geothermal energy in Ramsar

Arvin Afsar Keshmiri1, Hessam Oddin Salarian2

1Master of science (M.Sc), Islamic azad University Science and research Ayatollah Amoli branch; [email protected]

2 Assistant Professor, Islamic azad university Nour branch; [email protected]

Abstract

Today, with increasing urbanization, air conditioning industry has expanded subsequently, in order to obtain maximum performance with minimum energy consumption. Various techniques have been developed to optimize the air conditioning systems. Due to the large usage of compression refrigeration systems for cooling the buildings and high energy consumption of these systems various methods such as using of geothermal energy to reduce the energy consumption of these systems have been developed. Geothermal energy, solar energy and waste heat have immense application potential for production of refrigeration through combined vapour compression–absorption systems. In this paper, the aims of this paper are to develop a combined absorption compression refrigeration system and thermodynamic analysis of this cycle According to the terms of Ramsar city's geothermal resources. In this paper we have investigated the combined cycle formed of Compression refrigeration cycle and geothermal absorption refrigeration cycle. The ammonia–water pair is selected for the absorption system and ten different refrigerants are evaluated to find the best candidate for the vapour compression cycle: (R717, R32, R123, R22, R134a, R410a, R404a, R407c, R143a, and R152a). In the present study the best candidate for the novel combined cycle is selected which provides the highest cycle efficiency and the lowest degree of environmental damage. It is shown that the highest performances are obtained for R717 (COP = 6.38), R22 (COP = 5.69) and R134a (COP = 5.67). This refrigerating effect could be exploited in air-conditioning, ice production, storage of agricultural produce and fishery products. The geothermal temperature source in the range 343–349K supplies a generator operating at 335 K and the absorption cycle designed and develop to maintain the condenser of compression refrigeration cycle in 295 K. It is found that the COP can be improved by 34–37%, compared with the conventional cycle, under the same operating conditions, that is an evaporation temperature at 263 K and a condensation temperature of 308 K. Also the compressor power consumption reduces by 34.4%. For industrial refrigeration, the proposed system constitutes an alternative solution for reducing energy consumption and greenhouse gas emissions. Keywords: Absorption system; Combined system; Geothermal energy; Refrigeration system

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• This refrigerating effect could be exploited in air-conditioning, ice production, storage of agricultural produce and fishery products.

• This system presents an opportunity to reduce the continuously increasing electrical energy consumption.

• The new mentioned technology in this article will be increase the use of renewable energy in building's air-conditioning systems and industry.

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Experimental study of the effect of wind direction on the induced air flow rate in a two-sided wind-catcher

Mohammad Afshin1, Ahmad Sohankar2, Mojtaba Dehghan Manshadi 3, Mohammad Kazemi Esfeh4

1MSc of Mechanical Engineering, Isfahan University of Technology ; [email protected]

2Associate Professor of Mechanical Engineering, Isfahan University of Technology; [email protected] 3Assistant Professor of Aerospace Engineering, Malek Ashtar University of Technology

4 MSc of Mechanical Engineering, University of Yazd; [email protected]

Abstract

One of the most important requirements in designing and constructing of buildings is the ventilation systems. Nowadays due to the technological developments and also easy access to the fossil fuel resources and electricity, air conditioning in buildings is performed using mechanical or electrical driven air conditioning devices. But with increasing environmental issues, as well as increased energy consumption rates due to the higher living standards, natural ventilation has been reconsidered by many researchers and building designers. In designing of the natural ventilation systems, providing acceptable air quality and providing proper thermal environment should be considered at the same time. Studies indicate that wind-catchers are able to provide these two parameters. Wind-catcher performance is highly dependent on wind direction. In the present study effort is made to evaluate the performance of a two-sided wind-catcher based on wind tunnel measurements. The main driving force for wind-catchers to provide the natural ventilation in the buildings is the pressure field generated by the wind, so the ventilation performance of wind-catchers is usually predicted by determining the pressure coefficients. Thus, pressure coefficients over all the internal surfaces of the wind-catcher’s channels are measured in this study. Using measured pressure coefficients and analytical modeling, the natural ventilation efficiencies of wind-catcher are determined for various wind direction. For the first time in this study, the transition angle (the angle at which there is no airflow through the wind-catcher) is determined for the two-sided wind-catcher. It is found that the wind-catcher’s performance is reduced by increasing the wind angle, and it approaches to zero at transition angle. By increasing the incident angle from the transition angle, the ventilation capacity is increased and finally achieved to a maximum value at 90º angle of incident. It is observed that the transition occurs at an angle of approximately 42º.

Keywords: Natural ventilation, two-sided wind-catcher, pressure coefficient, wind tunnel


• There is no airflow through the windward face of the wind-catcher at the angle 42º. •The performance of two-sided wind-catcher is strongly influenced by wind direction. The windward face of the wind-catcher acts as suction device by exceeding the wind angle over the transition angle, • For all wind directions, the leeward face of the wind-catcher acts as a suction device and with increasing the wind direction from 0º to 90º, passive ventilation performance is increased. • At 90º angle of incident, the wind-catcher’s performance increases around 46% in comparison with zero angle of incident.

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Analysis the effects of time variations of thermal penetration depth on the acquired power from the underground air-soil channels

Mozhgan Nikoudel1,Alireza Zolfaghari2, Hossein Vatanpoor3

1Department of Mechanical Engineering, University of Birjand; [email protected] 2Department of Mechanical Engineering, University of Birjand; [email protected] 3Department of Mechanical Engineering, University of Birjand; [email protected]

Abstract

In this survey, the performance of underground channel and the required time for channel recovery and also, the effect of channel on the thermal conditions of surrounding soil have been studied under various conditions for air inlet velocity (from 1.5 to 4.5 m/s). Moreover, a criterion has been presented to determine the maximum acquired power of underground channel. The results show that changing in the system air capacity cannot significantly affect the thermal penetration depth parameter. So, the thermal penetration depth is only dependent to the working time period of system. Also, the results indicate that the air inlet velocity can meaningfully change the thermal efficiency of air-soil heat exchanger. Therefore, by increasing the air velocity from 1.5 m/s to 4.5 m/s, the average of heat transfer coefficient in the whole working period increases up to 200%. Moreover, by increasing the air capacity, ratio of the useful working time to the whole working time of system (include useful time and recovery time) is decreases. As well as, results indicate that the parameter "maximum acquired power per unit volume of soil" strongly depends on the length of system working time period. Keywords: underground channels, utilization maximum power, thermal penetration depth, recovery time


• Results show that an air-soil channel in underground which it is in proper depth, as the process begins, in the first five days and the days after that the power of process change with high and linear slope respectively. Thus for different work period more than 5 days, interpolation or extrapolation of exist information can be useful.

• Thermal penetration depth in surrounding soil just depends with work period length of process. Also, the system air capacity cannot significantly affect the thermal penetration depth in the soil.

• As the velocity of inlet air increases from 1.5 m/s to 4.5 m/s, the average of heat transfer coefficient increases up to 200% in each working period. Also, by increasing the system air capacity, the ratio of using time to total time (using time and recovery time) decreases.

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Modeling and evaluation of hybrid solar driven ejector-compression refrigeration system

1Mehdi Kalantarian ,2Amir HosseinShiravi ,3Mohammad Reza Assari

1Mehdi Kalantarian, NIOC; [email protected] 2Amir HosseinShiravi, JundiShapourUniversity of Technology; [email protected]

3Mohammad Reza Assari, JundiShapourUniversity of Technology; [email protected]

Abstract

In the paper, hybrid solar driven ejector-compression refrigeration system is explored. At this work,

thermodynamic models of simple ejector and vapor compression refrigeration system are studied and

solved by EES software. Both systems are analyzed with R600 refrigerant atestival climate of Dezfoul

in viewpoint of economic and efficiency. Then initial costs of solar system mentioned and current

costs are estimated due to consumption of electricity and fuel energy. Results are presented in tables 1

and 2. It is shown that using hybrid solar driven ejector-compression refrigeration system to prepare

the cooling load equivalent 11 tons of refrigeration (40 kW) for a small office or a residential

construction is economical.And its payback period is approximately 9 years.

Keywords: Ejector, Modeling , solar system , hybrid system , R600


• Results of the article can be applied for energy saving in industrial HVAC systems. • Using of solar system in warm region with good radiation cause energy saving and reduce of

global warming • The mentioned technology in this article will be increase the use of renewable energy in

HVAC&R because of its payback period (approximately 9 years) • Hybrid solar system can be used in a small office or a residential construction economicaly.

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The book of abstracts of

The 5rd International Conference on Heating, Ventilating and Air Conditioning

10-12 June 2014, Olympic Hotel Tehran-Iran

(400-word Abstracts)

www.hvac-conference.ir

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