Presentation on theme: "DR. CY YAVUZTURK, PH.D, C.E.M. COLLEGE OF ENGINEERING ARCHITECTURE AND TECHNOLOGY DEPARTMENT OF MECHANICAL ENGINEERING NET ZERO ENERGY BUILDINGS."— Presentation transcript:
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 Design Active 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 Buildings What is a Net Zero Energy Building (NZEB)? Active and Passive Approaches to Net Zero New Constructions and Retrofits Primary Technologies Design for NZEB Conclusions Resources
AN OVERVIEW United States Consumed about 100 QUADs (Quadrillion BTUs) of Energy in 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 200 7)
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 ), 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 Drawbacks Goals 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 Measures High-Performance Building Envelopes (Insulation, Fenestration) Passive Solar Heating/Cooling (Trombe Walls, Fabric Cooling) Day-Lighting Natural Ventilation
ACTIVE APPROACH TO NET ZERO High-Efficiency HVAC Equipment Ground-Source Heat Pump Systems Solar Thermal Solar Photovoltaics Wind Turbines Ocean Water Cooling Biomass Energy Combined Heat and Power Evaporative Cooling
OTHER APPROACHES TO NET ZERO Thermal Energy Storage Controls
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
NZEB ASHRAE NZEB Video
CONCLUSIONS More to be done!
RESOURCES DOE Websites EERE: Building Technologies Program Home Page EERE: Building Technologies Program Home Page NZEB Database NZEB Database NZEB Projects NZEB Projects Building Energy Modeling Software Building Energy Modeling Software Financial Opportunities & Tax Incentives Financial Opportunities & Tax Incentives ASHRAE US Green Building Council LEED LEED LEED Project Profiles LEED Project Profiles