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Transcript of The Role of Building Information Modeling to Enhance Energy Efficiency Analysis-libre
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Sustainability and BIM: The Role of Building Information Modeling to
Enhance Energy Efficiency Analysis
1/7/2014
University of Salford School of Built Environment Student name: Ahmad Naser Alsaadi
Roll number: @00312494
Module name: BIM Theory and Practice
Program of study: MSc BIM and Integrated Design
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Abstract
The energy analysis was too complex and expensive process, usually delayed to the end of the design.
How can BIM as approach to facilitate and improve the energy efficiency of design building? The
purpose of this paper is to demonstrate the role of BIM to optimize building energy performance and
provide an understanding of how the BIM system operates the whole energy simulation process. It
starts with overall explanation about the relationship between BIM and energy analysis, then definition
of energy modelling. Later the process of energy simulation and case study will be presented.
It is found that achieving an efficient energy design of buildings is the way to enhance sustainability and
economic saving by BIM system and tools. The difficulties of complexity and cost have been exceeded
through the advance of energy applications which are many of them became free and easy to access
with quick results and immediate feedback. However, there are various energy applications with
different plug-ins which provide dissimilar result, this matter leads the user to not depend on analysis
program.
1- Introduction
During last two decades, the design in fields of movie and music production, airplanes and machinery
have been developed significantly by information technology. Architecture, Engineering and
Construction (AEC) industry are now adopting a similar tools and approach in building design (Autodesk,
2005). The most advanced feature of these tools is delivering persistent and immediate feedback with
great margin from the traditional tools. These tools and approach are utilized in design, structure,
durability, management, energy efficiency and other building systems at different levels driving the
building technology towards a digital epoch (Che, Gao, Chen & Nguyen, 2010). This approach, which is
different from the conventional process of using CAD software, is known as Building Information
Modellig BIM. BIM is a itegrated proess hih is used to failitate the ehage of desig ad construction information to projet partiipats Moakher & Piplikar, . The built environment need of generating the sustainable buildings and enhancing the environmental
conscious is no longer a noble desire, but it is an urgent requirement. According to the American
Institute of Architects (AIA), the main source of greenhouse emission in USA is buildings. Within AEC
industrial and historical context, it has been unimportant to accurately understand the progressive
process of energy efficiency and sustainable design (Hodges, 2009). Hodges adds that globalization and
increasing the expectations of clients are forcing the industry professionals to design projects in more
sustainability and energy efficiency. Furthermore, (Dorta, Assef, Contero & Rufino, 2013), mentioned
different studies conclude that improving buildings energy performance leads to economic saving
between 30% (IDAE, 2008) and 75% (NAVARO, 2009), which means that energy efficiency is not only
sustainable, but also profitable.
This paper describes the relationship between BIM and energy analysis and its role as a regime to run
the process. Also its presents a progressive process of energy analysis to achieve the efficient
performance buildings through Building Information Modelling and evaluate the energy performance of
design alternatives in case study.
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2- Literature Review
2-1- BIM and Energy Analysis
There is a huge misconception of BIM in AEC (Architectural, Engineering, Construction) industry field
that BIM is no more than software, and that return to the confusion between the BIM process and BIM
model. (Dorta, Asset, Cantero & Rufino, 2013; NIBS, 2007) show that BIM acronym can be referred by
several aspects, as product (means a data set that structured to describe a building), as activity (is the
act of generating a building information model) or a system (the framework structured to manage and
coordinate the work and communication of the different stakeholders which maximize the efficiency
and quality). In addition, BIM is a system of planning, construction and operation of a facility during its
life-cycle (Stumpf, Kim & Jenicek, 2011). Generally, Building Information Modelling is a combination of
interacting processes, generating technologies, policies that creating a methodology to manage data
and design systems in digital format throughout the building life ( Succar, 2009). While, a BIM model is a
digital represetatio of the projets futioal ad phsial features tupf, Ki & Jeiek, . Krygiel and Nies (2008) mentioned that BIM model is a grammatically incorrect term commonly refers to
the digital models generated by software under the BIM process.
During design and construction, all building data such as materials, geometric information, chosen
systems of design, spaces, facility are required to be accessible in order to evaluate the building various
performance for instance, the energy performance. The different stakeholders of the design and
construction team, for example, architecture, structure, MEP, schedules and cost estimators, energy
develop their own specific models in separate way, and then integrate these models into rich, intelligent
and comprehensive one model (Meridian, 2008). The fundamental premise of this generated model is
collaboration by multidiscipline at different stages of the facility life-cycle to extract, insert or develop
information during the process (Stumpf, Kim & Jenicek, 2011). This necessary collaboration cannot
found without the availability of open and neutral specification of digital data format represented by the
Industry Foundation Classes (IFC), because each BIM tool has a propriety data structures for delivering
the requested data.
Figure 1 Data exchange between stakeholders in BIM
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Generally, analysis and assessment of building performance have great opportunities offered by the
advent of BIM and through its software tools (Mokher & Pimplikar, 2012). In particular, advanced energy
analysis is crucial to design strategies to minimize the energy consumption and assist in design energy-
efficiency, such as, energy and day lighting analysis programs which have been developing for years, but
rarely adopted by the design firms (Autodesk, 2005). Furthermore, under traditional Cad approach,
design and evaluate and efficient energy performance is very limited and painful, mostly used at late
stage of the desig proess he the projets harateristis aot e changed (Mokher & Pimplikar, 2012). Typically considered time-consuming and costly process that needs an intensive work to
regenerate the building model in order to analysis it (Kumar, 2008). Kumar (2008), also added an
obvious benefit that Building Information Modelling through the interoperability between its tools
offers the opportunity of export the digital models of the building to energy analysis software without
the need of recreate it from scratch. Now, with BIM tools such as Revit and Green Building Studio (GBS)
the energy analysis process became simple. All the designer needs is visit the GBS web service to
register ad doload the Gree Buildig tudio progra ito his drier to suit the projets odel, that required analysis, via internet after export the model from the generator tool (Revit) as gbXML
format or upload it directly through Revit software. Then after a few minutes the results will obtain
containing statistics, consumption and other information related to energy with recommendation to
enhance the design (Mokher & Pimplikar, 2012). All these findings based on the data attached to the
submitted model, include local standards, material information, type of building, location climate, etc.
As a result, within this process the designer can modify his model and resubmit it again in order to,
make decisions during the design early stage, set the most suitable energy system and achieve the
energy efficiency for the project.
2-2- Energy modelling
One of the most essential factors to ehae the projet sustaiailit is to uderstad a uildigs energy requirements. Buildings, such as houses, shops, offices and other functionalities, account for 40%
of world energy consumption and responsible for cause 36% of greenhouse emissions (European
commission, 2013; European commission, 2010). Improving the buildings energy performance is
inevitable, not only obtain the target of EU towards Nearly Zero-Energy Buildings (NZEB) by 2020, but
also to achieve the long term objectives of climate strategy by 2050 as set down in low carbon economy
roadmap (European commission, 2013; COM, 2011). A number of issues contribute to determine the
building energy needs and that simply does not related to people behaviour in energy consumption.
Furthermore, many of followed approaches and solutions within building different systems can affect
the eerg use diretl. For eaple, if the uildigs south eleatio has a lot of widows, it will provide enough natural light and minimize the electric illumination need. However, in this case, the building will
need more air-condition if the sun shading devices was inefficient. As a result, the designer must take
into account all energy related items and exploring the energy use in the building during the design
stage and that is why it is urgent to use the BIM process and its technology of energy simulation tools
(Krygiel & Nies, 2008). These simulation environments work through coupling the climatological
information with building loads. Such as, the required calculation elements by (Energy Performance of
Building Directive) (International Energy Agency, 2008). This shows in the following table.
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Table 1 the required calculation elements of EPBD
Through BIM, the energy model integrates all these elements to anticipate the demands of energy in
order to set the most appropriate HVAC system and other related parameters of the building
components based on an accurate energy needs and understanding the possible design impact on the
global environment.
2-3- Applying BIM for Energy Analysis
Using BIM approach, energy modelling and the process of integrated team is urgent to achieve the high-
performance energy and specified consumption goals (Cho, Chen & Woo). It must be realized that data
received from analysis of energy model is critical to recognize its effect on the design. The designer
should never consider the energy findings as a gospel, but the causes of these results should be
identified (Krygiel & Nies, 2008). The combination between energy analysis and BIM can maximize the
accuracy and efficiency, however, it can be tedious and time consuming if not done properly (Miller,
2010). So, it is essential to understand what results anticipated from energy analysis in different design
stages and how to implement it in design formation. Energy analysis findings can be linked with building
massing research to make a decision that determines the location of the building within the site at the
inception stages of the design (Autodesk, 2005). During the early design phase, the analysis data would
be used as comparative tool to enhance decisions making instead of focusing to measure the accuracy
of loads information, because many decisions are still undecided at the earlier stages of design or
probably will change in the future (Krygiel & Nies, 2008). For instance, based on the result gained from
analysis at the conceptual phase, the designer might find that tall building with small footprint
overcomes options with large built area and low elevations, or increasing the glass surfaces on the south
facade can optimize the day lighting, while it leads to an increase in energy demands to set a
appropriate air-condition system. According to Krygiel & Nies (2008), the analysis through BIM needs the
following tools to run energy modelling:
The project BIM model. A proper application for energy simulation. Apply the whole BIM approach, the full collaboration between the energy analyst, mechanical engineer and other team members, through the integrated approach, enhances the analysis
process, if the team members are unfamiliar with interpreting the data of energy analysis.
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2-4- Run the energy modelling process
2-4-1- BIM model
The energy modelling needs a well-built solid model in order to be successful. In some cases, the process
does not require all details and information that related to energy determined, but some basic
conditions have to be established. (Stumpf, Kim & Jenicek, 2011), outlined three different steps in the
process of energy modelling, as shown in figure 2.
Figure 2 The steps of energy modelling process
step one determines the energy requirements of the project. Challenges may emerge here because
typically any project has resources, specific cost target and schedules. To pass this step, all project
parties have to contribute in identifying the project needs alternative energy solution under the BIM
approach and during the planning phase.
Step two divides the process of energy modelling in two stages, concept and detailed design. The first
stage is related to building envelope and orientation, while the later is related to building elements and
details such as, materials, shape, and size.
Step three is an improvement process by using independent software to ensure the validation of energy
analysis results and support the essential needs. An example activity of this process is the repeated
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export of uildigs odel util ahiee the eerg goals or usig ore tha oe aalsis progra for comparison the findings.
There are a few basic conditions should be included within the model structure to ensure that energy
process run correctly and get the proper results. First of all, the designer must be certain about the
existence of the following points; floors and roofs must be included within the model, ensure that walls
touches the floors and roofs and building geometry must surround all areas required to analysis ( Krygiel
& Nies, 2008). After checking these three points, Stumpf, Kim & Jenicek (2011), noted that energy loads
a e estiated ad alulated ased o uildigs eelope harateristis idos, doors, uildig orientation and thermal zone. Similar but expanded key elements stated by Krygiel & Nies (2008),
project location, building envelope, room volumes and any specific settings of the application, should be
captured and transferred from the BIM model generator tool to the energy analysis application through
the ability of export a digital model format such as gbXML as mentioned before.
Project location Climate is the most important factor to determine the building exterior loads. The designer has to define
site properties within the modelling application.
Buildings envelope Although some of these following sound clear in concept, energy analysis cannot run without
establishing an accurate envelope such as, each space needs to be bounded by walls, roofs and floors.
Room volumes It can be said that all major BIM programs (Revit, Bently, ArchiCAD) work in similar approach to export
gbXML file. The minor difference between them is related to room volume ( Revit bound the spaces by
using Room Tag, while ArchiCAD using Zoon tool) (Stumpf, Kim & Jenicek, 2011). However what is
important to the process is to create and export a three dimensional bounded spaces.
Specific setting of the application Each program has its specific requirements to run the analysis process. For instance, before export the
gbXML file in Revit, many data needs to be addressed such as, building zip code and location, building
type and calculate the room volumes.
2-4-2- Energy modelling applications
Now, the BIM model has all needed energy information and ready to import as a gbXML into energy
application. Choosing the proper analysis tool depends on many factors for example, the project phase,
skills of user or time availability. The following data are taken from ( Krygiel & Nies, 2008), (Mokher &
Pimplikar, 2012), (Kumar, 2008) and (Pallapalli, 2010), for five tools presented as a comparision.
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Application type Advantages Disadvantages IES Integrated Environment
Solution
Present a high level of accuracy and
interoperability with BIM Operate the whole environmental series
(analysis, day lighting,
CFDs).
Complex for the user. Expensive comparing with relative tools. The inability to import a large number of gbXML. Saving the IES files in many of separate files
such as, light, cfd,..etc. Ecotect It has a friendly graphical interface. Easy to run and use. The application is supported with other
tools (day lighting,
weather, ventilation,
airflow analysis). Produce annual and peak loads.
It has challenges with importing, exporting BIM
model directly depends
on program used for
example Revit, but
Autodesk about to build
API-level integration
between them.
eQUEST Free tool. Has the ability for energy simulation including
(heat loads, HVAC,
climate data). The ability to import from CAD programs.
Cannot export geometry to programs. Cannot estimate the thermal comfort and
analysis the natural
ventilation.
Design Builder Has the ability to export and import models. Has a great ability for analysis (heat loads,
HVAC, climate data).
Relatively expensive. Does not have the ability to simulate the heat and
cold storage that gained
seasonally. Green Building Studio Free service. Produce quick graphical simulation for building
energy performance.
The survey details are not high. It has limited choices, if the building does not
suitable for these
options, the result will
be inaccurate.
Table 2 comparison between most common analysis applications
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2-4-3- Optimizing the energy use
This process occurs during the operation of energy analysis to compare between design options.
Optimizing the energy use relies on realizing the relative energy that affect the building performance.
Krygiel & Nies (2008), mentioned the following example which provides a good illustration in terms of
comparing and choosing the most appropriate option. The example project has two alternatives for an
energy comparison, design 1: does not include sunshades, design 2: includes sunshades. The design aims
to supply a saving in cost throughout the building life-cycle which justifies the extra cost of installing the
shades to the project. Green Building Studio service was used in this analysis after export the project
BIM model as gbXML from Revit. After a few minutes the result, shown in figure 3, came back to prove
that shaded option will reduce the life-cycle energy cost.
Figure 3 a result of comparison between two BIM models was run in GBS
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2-5- Case study of CESS Building (Stumpf, Kim & Jenicek, 2011)
2-5-1- general information
Project name and location: Community Emergency Service Station (CESS) at Fort Bragg, North Carolina.
Project facilities: police services, ambulance and fire fighting.
Project size: 8,300 square feet.
Project objective: achieve LEED-NC 2.2 Platinum rating.
Project standards: ASHRAE 90.1-2004.
Comparison factor: Annual energy cost.
Project requirements: A charrette process, held at the earliest stage and for four days, used to
understand the partiipats interests, generate solutions and specify the project target. Project challenges: firstly, it was important to supply the stakeholders with result of energy analysis at
the beginning and during the charrette. Secondly, energy analysis considered as a time consuming
because the process of re-input all data of the project to generate the energy result.
BIM tools: Revit, Revit MEP, Green Building Studio GBS and eQUEST.
2-5-2- Energy modelling process
The process divided into two sub-processes based on project phases:
The macro-level: focusing on selecting the most appropriate shape, size, orientation. The micro-level: This related to building details such as, material of the envelope and energy systems of the building.
Figure 4 CESS Building BIM model.
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2-5-2-1- Concept phase (macro-level), See figure 5
Step1- The architect developed three alternatives: A) Two separate buildings. B) Single building with
two storeys. C) Single building with one storey.
Step2- Estimating the three options annual cost of energy in order to choose the most efficient
envelope. An important point to mention that the summer cooling is the most dominant load for the
building which depends on the project location. So, according to analysis had been done the mechanical
engineer, the C option was the chosen alternative.
Step3- Considering the best orientation to decrease energy needs. Based on a functional requirement,
the architect wanted a 15 degree rotation for the part of apparatus room to facilitate the vehicles
movement. The analysis found the highest energy cost will be generated when the orientation becomes
120 degree, while the energy cost will be very low if the building long axis face the south. In order to
meet the architect request the annual energy cost increased only 75$, which considered a small amount
to meet such important functional requirement.
Figure 5 concept phase process (macro-level)
2-5-2-2- Detailed design phase (micro-level), see figure 6
Six groups of building elements were considered in analysis using GBS after export the BIM model as
gbXML from Revit MEP, HVAC (10 options), glazing (17), roof (20), walls (15), lighting (4) and lighting
control (3). The result showed that the greatest effect on annual energy cost was the HVAC options.
However, the lowest impact was the lighting control.
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Figure 6 detailed design phase (micro-level)
2-5-3- Optimizing process
A comparison between the baseline model and proposed design model, that created by energy analysis
experts using GBS and eQUEST to validate the CESS building model. The findings were validated
according to ASHRAE 90.1-2004 annual energy cost standards. As a result the difference between
baseline model and proposed model was about 35-40% at the confidence level of 80-85%, which shows
that baseline model was successful to achieve ASHRAE 90.1-2004 with 6% difference while the proposed
was 15.5%.
2-5-4- lesson learned
Achieving an optimal energy design needs a collaborative and innovative strategies for design and
analysis can be run by BIM. Even the most expert mechanical engineers cannot analyse the energy
performance perfectly without the efforts of other team members. BIM supplies the analysis phases
with intelligent data for direct use.
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3- Conclusion and recommendations
Considering building energy aspects and efficient performance are become the trend to achieve
sustainable design which is now most required because of the growing emphasis on environmental
conscious. This paper has presented the role of BIM as approach to run and manage the energy analysis
process. Also, it provided an overall demonstration about the progressive process of the energy
simulation. Furthermore, a case study has been examined to explore how energy design alternatives can
be optimized and compared by BIM tools to obtain efficiency.
The integration between BIM concept and environmental parameters such as, location climate and
orientation can maximize the building energy performance. Using the energy analysis applications under
the BIM approach during the early stage of design would generate efficient energy buildings. The ability
of BIM tools to produce a basic model, that has all required energy data, is the key success of building
performance analysis through energy tools. The most important role of energy tools during any level of
design phase is comparing between design alternatives, according to the project identified goals and the
chosen energy standards, to determine the most appropriate options. That can be happened by the
capabilities of energy software such as, GBS and Ecotect which facilitate the professioals access and quick feedback.
So, it is recommended to use the energy programs, for example, Green Building Studio, in the beginning
to configure the building shape and orientation, while during the detailed level, to specify the most
efficient energy systems of the buildings. However, the analysis process requires from project
participants to do not completely rely on the result gained from one application, but it should be
compared with other applications results. The energy tools capabilities needs to be combined into
sustainable design and BIM regime to achieve the specified energy goals.
Finally, due to importance of this topic for the AEC industry and environment needs, it is valuable to
standardise the energy simulation process under BIM system as a workflow routine in future studies in
order to optimize the building energy performance.
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References
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