Presentation on theme: "NET ZERO ENERGY BUILDINGS"— Presentation transcript:
1NET ZERO ENERGY BUILDINGS Dr. Cy yavuzturk, ph.d, c.e.m.College of engineering architecture and technologyDepartment of Mechanical engineering
2BACKGROUND Assistant Professor in Mechanical Engineering Teach and Conduct Research inThermodynamics, 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 SubcommitteeFormer Chair of Research of Geothermal Energy Utilization Subcommittee
3OUTLINE 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
4AN OVERVIEWUnited States Consumed about 100 QUADs (Quadrillion BTUs) of Energy in 2007.100 QUADs = 100,000,000,000,000,000 BTUsIn Other Words800,007,000,000 gallons (US) of gasoline3,040,026,600,000 liters of gasoline3,600,000,000 tons of coal97,043,400,000,000 cubic feet of natural gas29,307,100,000,000 kWh of electricity
5AN OVERVIEWEnergy Consumption by Source (DOE Energy Data Yearbook 2007)
6AN OVERVIEWWhere Do We Consume Energy? (DOE Energy Data Yearbook 2007)
7AN OVERVIEWBuilding Energy Consumption Distribution (DOE Energy Data Yearbook 2007)
8ENERGY SAVINGS IN BUILDINGS Approximately 48 QUADs consumed in Buildings36% Space Air-Conditioning -> 17.3 QUADs27% Space Illumination -> 12.9 QUADs14 % Water Heating & Refrigeration -> 6.7 QUADs11 % Electronics & Computers -> 5.3 QUADs2% Cooking -> 1 QUAD10 % All Other Consumption -> 4.8 QUADsSignificant Opportunities in Reducing Energy Consumption Exist!1% Reduction = 0.48 QUADs
9ENERGY SAVINGS IN BUILDINGS 0.48 QUADs = 480,000,000,000,000 BTUsIn Other Words3,843,360,000 gallons (US) of gasoline14,592,127,680 liters of gasoline17,280,000 tons of coal465,808,320,000 cubic feet of natural gas140,674,080,000 kWh of electricityHowever, Technology is available & Economics are favorable to do more than reducing Consumption.Reduction coupled with Production of Energy, leading to Net Zero Energy Buildings.
10JUSTIFICATION FOR NET ZERO 71% of All Electricity Consumed is Consumed in Buildings! This is a Huge Burden on:Electrical SystemEnergy Resource AvailabilityEmissionsEconomic ViabilityTo make things worse:The Commercial Sector is Expected to Grow by Average 1.5% Annually in the next DecadeEconomic Expansion and Population Growth Demands more Building SpaceEnergy Demand is Growing faster than Energy Conservation Measures taken.
11JUSTIFICATION 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/sqftIf all buildings in the commercial stock had been designed using the Model Energy Code (ASHRAE Std ), the EUI would be about 50 kBTU/sqft41% 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
13NET ZERO ENERGY BUILDINGS BUT THERE IS SIGNIFICANT WASTE!
14NET 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
15NET 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.
16NET 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!
17PASSIVE 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
18ACTIVE APPROACH TO NET ZERO High-Efficiency HVAC EquipmentGround-Source Heat Pump SystemsSolar ThermalSolar PhotovoltaicsWind TurbinesOcean Water CoolingBiomass EnergyCombined Heat and PowerEvaporative Cooling
19OTHER APPROACHES TO NET ZERO Thermal Energy StorageControls
20NEW 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!
21THE FUNDAMENTALS A Building’s Energy Consumption can be broken into: Envelope NeedsSensible ConductionSolar LoadsInfiltration Loads (Sensible and Latent)Occupant NeedsSensible and Latent NeedsFresh Outside Air RequirementsSystem EfficienciesMechanical Component EfficienciesConfiguration and System Control Strategies
24THE FUNDAMENTALS Inefficiencies: About 15%-20% of Energy Savings could be achieved in Commercial Buildings ifEquipment Inefficiencies could be eliminatedSystem Configuration ImprovementsSystem and Sub-System Operations could be optimizedWhole-Building system control and operation algorithms could be implementedAnd with some (even minor) attention to detail in the operation of mechanical systems
25DESIGN FOR NZEB Building Envelope Measures Orientation – optimize natural daylighting, passive solar heat in winter & minimize solar heat gains through fenestrationsIncrease R-values of walls and roof with enhanced envelope insulationExternal shading devices to minimize direct sunlight in summer (fins, overhangs, plants)Skylights for natural daylighting and monitors to bring daylight into building coreOptimize envelope surface performance (reduce glazing areas in E/W facing surfaces, increase in N/S)
26DESIGN FOR NZEB Equipment & Lighting Measures High-efficiency lighting controlled with occupancy sensorsDaylighting controls to lower lighting and cooling requirementsHigh-efficiency water heating systems to reduce stand-by lossesMaximum use of outside air ventilation when outside temperatures are low (free cooling)Demand controlled ventilation with occupancy sensorsGround source heat pump systems for higher COP’sVariable speed fans and pumps to reduce energy distribution energy at part load conditions
27DESIGN FOR NZEB Waste heat recovery Evaporative cooling Internal energy wheelingOptimized controlsOccupant and operator training
28DESIGN FOR NZEB Renewable Energy Measures Solar thermal collectors for service water as well as space heatingPhotovoltaic panels for direct electricity generationElectricity generation from wind energyGeothermal energy utilizationBiomassOther renewable energy technologies as appropriate
29AN EXTREME CASE STUDY IDeAs Z-Squared Design Facility Located in San Jose, CARetrofit of a 1960’s Building6,560 sqft, 2-storyUrban SettingCurrently OperationalZ-Squared (net zero energy and net zero carbon emission
30AN EXTREME CASE STUDY All Electric 30kW Roof-Mounted PV Arrays Heating and Cooling via GSHPHeating System is Radiant Hot WaterCooling System is AirSignificant Lighting Controls via Occupancy SensorsDaylighting Monitors for Lighting of Building CoreElectrochromic Glass on Fenestrations to Reduce Solar GainsSunshades with Integral PV Cells
33RESOURCES DOE Websites ASHRAE US Green Building Council EERE: Building Technologies Program Home PageNZEB DatabaseNZEB ProjectsBuilding Energy Modeling SoftwareFinancial Opportunities & Tax IncentivesASHRAEUS Green Building CouncilLEEDLEED Project Profiles