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Energy Efficiency and Renewable Energy Technologies for Public Facilities

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					Energy Efficiency and Renewable Energy Technologies for Public Facilities
September 8, 2004 Terri Walters State and Local Initiatives terri_walters@nrel.gov

High Performance Public Buildings: Overview
• • • • • Design Process Site Selection Lighting & Daylighting Building Shells Mechanical Systems and Controls • Renewable Energy • Commissioning

DOE Zero Energy Buildings Vision
“By the year 2020, the United States will be constructing a significant number of buildings that:
• meet their own energy needs by utilizing solar or other renewable resources, • have no on-site or off-site carbon emissions, • reduce utility peak electrical demand, • optimize the health and productivity of their occupants, • provide energy security from natural disasters and extended power outages.”

Zero Energy Buildings Systems Integration
Building Technologies
Efficiency Technologies & Building Integration

Solar
PV and Solar Hot Water Technologies

Zero Energy Buildings Goal
Fuel Cell Technology & Hydrogen Infrastructure Combined Heat and Power Technologies

Hydrogen & Fuel Cells

Distributed Energy

Whole Buildings Focus
Evaluate a wide range of energy-efficient strategies, working together
Passive solar heating Shading High Efficiency HVAC Daylighting Better HVAC Controls Better windows Economizer cycle Energy efficient lights Reduced infiltration and ballasts Lighting controls Reduced duct leakage Insulation Photovoltaics Thermal mass Distributed Generation Combined Heat and Power

Integrated Design
• Modern Buildings function as complex systems • Whole building design is critical for success

Early Planning is Critical Opportunity Time

Design Process is Cross-Cutting

Design Consideration for Municipal Buildings
• Ensure fiscal discipline
– Energy efficient and self-generation reduces life cycle cost

• Provide safe and healthy workspace
– Building comfort increases productivity

• Address reliable and secure energy supplies
– Especially important for critical services and emergency facilities

• Demonstrate community leadership
– Municipal governments set the tone by using RE and EE

New Building Technologies
• • • • • Cool and Green Roofs Active and Passive Solar Daylighting and lighting controls High Efficiency Windows Energy management and tracking systems • Onsite power generation

Green Roof Technologies Reduce Cooling Loads
• Reduces cooling load (insulates) • Reduces stormwater runoff as well as cleans runoff • Reduces urban heat island effect

Cool Roofs
• “Cool” roofs reduce cooling load by up to 40%
– Reflect sun’s thermal energy instead of absorbing it – Reduces urban heat island effect

Solar Thermal Systems
• Solar collectors produce heat for many applications
– – – – Domestic hot water Pool heating Space heating Absorption cooling

• Can provide 40%-80% of building needs

Solar Thermal for Cooling: Absorption Chillers
• Texas has excellent solar resources but mainly needs cooling, not heating. • Absorption Chillers can use solar thermal collectors as a heat source.
– Absorption chillers used extensively in New York. – Hybrid Solar/Fossil absorption chillers available.

• Austin Energy’s Sand Hill building uses solar absorption chillers.

Solar Thermal for Air Heating
• Transpired Solar Collectors are solar air preheating systems • Collector is dark metal wall with holes • Typical system payback 3-12 years

Desiccant Cooling Systems
• Non CFC, energy efficient space conditioning • Heat driven, like absorption cooling • Dehumidifies and cleans the air, making it useful for hospitals and other clean air environments • Perform best in humid environments

High Efficiency Windows
• Texas SB 5 requires windows with a Solar heat gain coefficient (SHGC) of 0.40. • SHGC measure how much solar heat is allowed through the window. Lower is better! • Current Texas buildings average .73

Diffusing Skylights
• Diffusing skylights can reduce both electric and cooling loads.
– Skylights reduce electric loads by replacing lighting – Reduce cooling loads through reflectivity as well as reduced heat loads from lighting.

Daylighting Strategies Help Reduce Electrical Loads

Daylighting and Lighting Controls can be used throughout the building

Integration of Lighting and Lighting Controls
• Integration of natural daylighting, artificial lighting and lighting controls is important • Note the natural daylight is indirect
– avoids glare problems – reduces direct heat gain

Ground Source Heat Pumps
• Heat Pumps make use of the constant temperature of the earth
– Fluid is pumped through pipe loops placed underground – Can be used for heating and cooling.

Photovoltaics
Building Integrated
• 4 Times Square, NYC • Demonstration of several energy technologies • PV Curtain Wall on upper floors

Building-Integrated PV
• Any PV system can be integrated with a building • Building Integrated PV tends to have lower efficiencies than standard PV • NREL research is focused on raising these efficiencies.

Integrated PV Examples

Energy Management Controls
• EMC optimize performance of all buildings systems • Complex array of sensors and controls to ensure efficienct use of energy. • Balance Economizers, Variable Air Volume fans, Daylighting & Lighting

On-Site Power Generation
• Power Quality Power Reliability
– Critical Government services – Hospitals – Communications – Emergency services
Courtesy Powerlight Corporation

Combined Heat and Power
• Combining heat and power increases efficiency • Future of CHP
– Microturbines – Fuel Cells

Case Studies

Pennsylvania DEP: Cambria Office Building

• Energy Efficient Features
– – – – – Efficient envelope Under-floor air distribution system Ground-source heat pumps 30% energy savings 18 kW PV system Daylighting / lighting system 87 EnergyStar Rating

Jefferson County, CO District Attorney Building
• • • • 52,000 square feet Daylighting Passive Solar High-quality, low cost

Foothills Community Hospital Boulder, CO
• First LEED Hospital – Silver certified • Combined Heat and Power • Efficient HVAC and Lighting • White Roof • Water Conservation • Green Power

Galt House, Lousville KY
• World’s largest Ground Source Heat Pump project • GHP system cut energy use in half in 750,000 sq. ft. hotel • Savings
– 20-50% on installation – $25,000/mo. on energy – 25,000 sq.ft. space

• 15 years of success

Low Temperature Solar Hot Water: Barnes Field House, Fort Huachuca, AZ
 2,000 square feet of unglazed collectors  Meets 49% of pool heating load  Installation: $35,000  Annual savings: $5,400  Older project, 1980

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High Temperature Solar Hot Water: Social Security Admin. Philadelphia.
• Reheats Recirculation Loop • Cost $58,000 • Delivery of 143 million Btu/year estimated • Installed 2004.

High Performance Buildings: Texas
• Austin City Council resolution in 2000
– All new municipal buildings LEED Silver

• New green buildings:
– Austin Energy: Sand Hill Center – Austin Library: Carver Branch – Combined Emergency Center

Future Austin Green Buildings

Summary
• Buildings are complex systems and require an Integrated Design Process • Early planning crucial • EE and RE innovations make Zero net energy achievable • Leverage existing as well as emerging technologies • Public buildings can lead the way for a more efficient building sector.


				
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