NET ZERO ENERGY BUILDINGS
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DR. CY YAVUZTURK, PH.D, C.E.M. COLLEGE OF ENGINEERING ARCHITECTURE AND TECHNOLOGY DEPARTMENT OF MECHANICAL ENGINEERING NET ZERO ENERGY BUILDINGS
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NET ZERO ENERGY BUILDINGS. Dr. Cy yavuzturk, ph.d , c.e.m . College of engineering architecture and technology Department of Mechanical engineering. BACKGROUND. Assistant Professor in Mechanical Engineering Teach and Conduct Research in - PowerPoint PPT Presentation
Transcript of NET ZERO ENERGY BUILDINGS
DR. CY YAVUZTURK, PH.D, C.E .M.
COLLEGE OF ENGINEERING ARCHITECTURE AND TECHNOLOGY
DEPARTMENT OF MECHANICAL ENGINEERING
NET ZERO ENERGY BUILDINGS
BACKGROUND
Assistant Professor in Mechanical Engineering
Teach and Conduct Research in Thermodynamics, Heat Transfer, Energy Engineering,
HVAC, Sustainable DesignActive Member of the American Society of
Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) Chair of Solar Energy Utilization Subcommittee Former Chair of Research of Geothermal Energy
Utilization Subcommittee
OUTLINE
An Overview of the Energy Consumption ‘Landscape’ in the US.
Significance of Energy Savings in BuildingsWhat is a Net Zero Energy Building (NZEB)?Active and Passive Approaches to Net ZeroNew Constructions and RetrofitsPrimary TechnologiesDesign for NZEBConclusionsResources
AN OVERVIEW
United States Consumed about 100 QUADs (Quadrillion BTUs) of Energy in 2007.
100 QUADs = 100,000,000,000,000,000 BTUs In Other Words
800,007,000,000 gallons (US) of gasoline 3,040,026,600,000 liters of gasoline 3,600,000,000 tons of coal 97,043,400,000,000 cubic feet of natural gas 29,307,100,000,000 kWh of electricity
AN OVERVIEW
Energy Consumption by Source (DOE Energy Data Yearbook 2007)
AN OVERVIEW
Where Do We Consume Energy? (DOE Energy Data Yearbook 2007)
AN OVERVIEW
Building Energy Consumption Distribution (DOE
Energy Data Yearbook 2007)
ENERGY SAVINGS IN BUILDINGS
Approximately 48 QUADs consumed in Buildings 36% Space Air-Conditioning -> 17.3 QUADs 27% Space Illumination -> 12.9 QUADs 14 % Water Heating & Refrigeration -> 6.7 QUADs 11 % Electronics & Computers -> 5.3 QUADs 2% Cooking -> 1 QUAD 10 % All Other Consumption -> 4.8 QUADs
Significant Opportunities in Reducing Energy Consumption Exist!
1% Reduction = 0.48 QUADs
ENERGY SAVINGS IN BUILDINGS
0.48 QUADs = 480,000,000,000,000 BTUs In Other Words
3,843,360,000 gallons (US) of gasoline 14,592,127,680 liters of gasoline 17,280,000 tons of coal 465,808,320,000 cubic feet of natural gas 140,674,080,000 kWh of electricity
However, Technology is available & Economics are favorable to do more than reducing Consumption.
Reduction coupled with Production of Energy, leading to Net Zero Energy Buildings.
JUSTIFICATION FOR NET ZERO
71% of All Electricity Consumed is Consumed in Buildings! This is a Huge Burden on: Electrical System Energy Resource Availability Emissions Economic Viability
To make things worse: The Commercial Sector is Expected to Grow by Average
1.5% Annually in the next Decade Economic Expansion and Population Growth Demands
more Building Space Energy Demand is Growing faster than Energy
Conservation Measures taken.
JUSTIFICATION FOR NET ZERO
Consider the following (DOE 2006 Scenario): The current stock of commercial buildings have an
approx. Energy Use Intensity (EUI) of about 85 kBTU/sqft
If all buildings in the commercial stock had been designed using the Model Energy Code (ASHRAE Std. 90.1-2004), the EUI would be about 50 kBTU/sqft
41% Energy Savings! Tremendous Potential for Energy Savings Already
Exits. And, if PV were to be added to commercial roofs EUI
may be as low as 35 kBTU/sqft! Add ‘Solar Energy Measures’, HVAC Equipment
Efficiency Improvements (mostly modest!) -> EUI further reduces to 15.5 kBTU/sqft
NET ZERO ENERGY BUILDINGS
GETTING CLOSER!
NET ZERO ENERGY BUILDINGS
BUT THERE IS SIGNIFICANT WASTE!
NET ZERO ENERGY BUILDINGS
ZERO is the Crossover Point between a Building that consumes a Resource and one that produces the Resource.
It is the point where Energy Needs of a Building has No Impact.
Zer0 - Sum of All Energy Flows are Equal but Opposite. ∑E=0
NET ZERO ENERGY BUILDINGS
Several Definitions (or ways of accounting) Exist: Net Zero Site Energy Building – Produces as much
renewable energy as it uses in a year at the site. Net Zero Source Energy Building – Produces (or
purchases) as much renewable energy as it uses in a year when accounted for at the source.
Net Zero Energy Costs Building – Receives as much money from the Utility Co. for on-site production of renewable energy as it pays in a year for energy services.
Net Zero Energy Emissions Building – Produces (or purchases) enough emission-free renewable energy to offset emissions from all energy used in a year.
NET ZERO ENERGY BUILDINGS
No ‘Best’, All-Encompassing Definition Exists!Each Approach has Merits as well as
DrawbacksGoals of the Building Owner and Building Use
Characteristics also play a significant role as to what approach may be the most reasonable.
However, one Rule remains constant for new-constructions and retrofits:
REDUCE DEMAND FIRST, SUPPLY SECOND!
PASSIVE APPROACH TO NET ZERO
Building Geometry and Orientation MeasuresHigh-Performance Building Envelopes
(Insulation, Fenestration)Passive Solar Heating/Cooling (Trombe Walls,
Fabric Cooling)Day-LightingNatural Ventilation
ACTIVE APPROACH TO NET ZERO
High-Efficiency HVAC EquipmentGround-Source Heat Pump SystemsSolar ThermalSolar PhotovoltaicsWind TurbinesOcean Water CoolingBiomass EnergyCombined Heat and PowerEvaporative Cooling
OTHER APPROACHES TO NET ZERO
Thermal Energy StorageControls
NEW CONSTRUCTION & RETROFIT
Approaches to Net Zero will be different if New Construction or Retrofit.
Some Technologies may be ‘too late’ for an already existing building.
Nevertheless, with exceptions, the overall design approach is fundamentally the same.
It’s all about judicious use of energy to reduce cost and ‘save the planet’ in the process!
THE FUNDAMENTALS
A Building’s Energy Consumption can be broken into: Envelope Needs
Sensible Conduction Solar Loads Infiltration Loads (Sensible and Latent)
Occupant Needs Sensible and Latent Needs Fresh Outside Air Requirements
System Efficiencies Mechanical Component Efficiencies Configuration and System Control Strategies
THE FUNDAMENTALS
The Building Envelope:
THE FUNDAMENTALS
Internal Loads:
THE FUNDAMENTALS
Inefficiencies: About 15%-20% of Energy Savings could be achieved
in Commercial Buildings if Equipment Inefficiencies could be eliminated System Configuration Improvements System and Sub-System Operations could be optimized Whole-Building system control and operation algorithms
could be implemented And with some (even minor) attention to detail in the
operation of mechanical systems
DESIGN FOR NZEB
Building Envelope Measures Orientation – optimize natural daylighting, passive
solar heat in winter & minimize solar heat gains through fenestrations
Increase R-values of walls and roof with enhanced envelope insulation
External shading devices to minimize direct sunlight in summer (fins, overhangs, plants)
Skylights for natural daylighting and monitors to bring daylight into building core
Optimize envelope surface performance (reduce glazing areas in E/W facing surfaces, increase in N/S)
DESIGN FOR NZEB
Equipment & Lighting Measures High-efficiency lighting controlled with occupancy
sensors Daylighting controls to lower lighting and cooling
requirements High-efficiency water heating systems to reduce
stand-by losses Maximum use of outside air ventilation when outside
temperatures are low (free cooling) Demand controlled ventilation with occupancy sensors Ground source heat pump systems for higher COP’s Variable speed fans and pumps to reduce energy
distribution energy at part load conditions
DESIGN FOR NZEB
Waste heat recovery Evaporative cooling Internal energy wheeling Optimized controls Occupant and operator training
DESIGN FOR NZEB
Renewable Energy Measures Solar thermal collectors for service water as well as
space heating Photovoltaic panels for direct electricity generation Electricity generation from wind energy Geothermal energy utilization Biomass Other renewable energy technologies as appropriate
AN EXTREME CASE STUDY
IDeAs Z-Squared Design Facility Located in San Jose, CA Retrofit of a 1960’s Building 6,560 sqft, 2-story Urban Setting Currently Operational Z-Squared (net zero energy and net zero carbon
emission
AN EXTREME CASE STUDY
All Electric 30kW Roof-Mounted PV Arrays Heating and Cooling via GSHP Heating System is Radiant Hot Water Cooling System is Air Significant Lighting Controls via Occupancy Sensors Daylighting Monitors for Lighting of Building Core Electrochromic Glass on Fenestrations to Reduce
Solar Gains Sunshades with Integral PV Cells
CONCLUSIONS
More to be done!
RESOURCES
DOE Websites EERE: Building Technologies Program Home Page NZEB Database NZEB Projects Building Energy Modeling Software Financial Opportunities & Tax Incentives
ASHRAEUS Green Building Council
LEED LEED Project Profiles
