Paul Crovella Department of Sustainable Construction Management and Engineering 8/2/11 How old is your computer? How old is your car? How old is your house? Green – Reduced negative environmental impact (LEED, Green Globes, CHPS, ICC 700) Sustainable – No negative environmental impact (Living Building Challenge) Restorative – Positive environmental impact (photocatalytic cements) In terms of alternative energy sources, many owners are interested in “net” zero energy buildings (site vs. source). Conduction, convection, and radiation are the three methods: How would we make a good insulation to stop heat transfer? By Conduction? Thermal conductivity inversely proportional to density By Convection? Film coefficient depends on rate of fluid flow and type By Radiation? Emissivity depends on material surface characteristics. Vacuum Insulated Panels for attic entries. Insulation tester…. Any warm body radiates, and the radiation that it emits is either reflected, absorbed, or transmitted The cameras offer both qualitative as well as quantitative opportunities. Their use in forensics is extensive, development of standards is ongoing for use in commissioning In this case, the frost on the roof is the result of the roof radiating to deep space on a clear night. What does the frost pattern tell us about the material temperatures? Energy improvements to building shell Installed appearance Loss of seals, infiltration Note cavities with light fixtures Infiltration during blower door testing Early Energy Use in Buildings - 1994 Juneau, Alaska Avalanche on April 16 2008 cuts lines supplying (cheap) hydropower. Using back up diesel generators raised rates by 400% (from 11 to 53 cents per kWh) 31,000 residents cut electricity use by 30% in two weeks – stores ran out of clothespins, etc One month after price returned to normal (after repairs) the electricity use is only 13% less than previous level. Information from http://www.nytimes.com/2008/05/1 4/us/14juneau.html?_r=2 What if we could come up with a way to capture the incoming solar energy and convert it at a high efficiency to provide useful work? Presenting the selective coating….. Solar radiation that strikes a surface is either absorbed, transmitted, or reflected. The absorption of material is equal to its emittance (at the same temperature). Incoming visible light can be absorbed and converted to IR. To heat water in the winter the heat in the water must be trapped. With a selective absorber, incoming visible light can be absorbed, converted to heat (IR) and then re-radiance can be blocked by glass and convection can be controlled by vacuum Integral storage systems – Flat plate collectors – very common in warm climates for DHW or preheat. Works in warm climates and with diffuse radiation Evacuated flat plate collectors – hard to maintain vacuum in a box Evacuated tube collectors – Vacuum is like a thermos bottle, eliminates convection loss. Reflector concentrates direct irradiation Works in cold climates and works best with direct radiation Single circuit systems – Used where there is no danger of frost (or even night radiation) Double circuit systems – propylene glycol is kept separate from potable water by use of a heat exchanger. Drainback systems are also available (no antifreeze) Flow Pump – Tank can be located anywhere relative to the collector. Thermosiphon – hot water will rise, so if the tank is above the collector, the fluid will circulate constantly w/o pump. Tanks – a solar system can provide Pre-heat in a separate tank or in the main tank Tubes cost 50-100 each. 20 tubes will supply most of the DHW during 9 months of the year in CNY. Tubes are made of metal alloys and glass, but none of the materials is highly toxic Efficiency most commonly referred to is “Solar fraction” = percent of daily DHW energy that came from sun. EVT Collector efficiency about 80% - good payback without government help http://www.sunviewer.net/portals/SUNYESF/ Efficiency = captured power flux/incident power flux Efficiency =( Liters x ΔT (C) x 633/Minutes/Irradiance) x 100 Natural Daylight in schools improves students’ performance (7 to 18% Heschong, et al 2002) First LEED certified home in NYS – built by Kevin Stack - Adjunct Instructor Vancouver Convention Center - The six-acre rooftop garden is crafted as a habitat for the 400,000 native plants and grasses growing there, as well as for birds and bugs (it houses hives for 60,000 bees). Energy efficient – in operation and construction Resource efficient - in operation and construction Non-polluting – operation and production Durable – so that they can be used for a long time Adaptable for many uses – so that they can be easily reused Healthy – few chemicals given off, no mold, fresh air Beautiful and Comfortable – so that people will want to use and re-use them From “Green Building and Sustainablility” by John Straube - Building Science Press U.S. Building consume 2/3 of all electricity, 1/3 of all energy www.energystar.gov CFLs use one fifth the energy and last 10 times as long as incandescent, LEDs last 2-5 times as long as CFLs, and use equal or less energy www.wikipedia.org Permeable pavings Commercial buildings use almost 20% of the U.S. drinking water supplies. www.Energystar.gov Dual flush toilet fixtures Green roofs of the future? Wind farms in Madison County (1 hr from Syracuse) 15.4 KW of PV panels on Walters Hall at SUNY - ESF Worldwide energy use continues to increase Using new materials in different ways will require a thorough understanding of the materials’ properties Materials will be evaluated in many ways, not just based on first cost. 100 year old slate shingles Modern slate alternative - will it last? Schools to apartments Fire house to Odd Fellows Hall to Community Museum Barns to homes Indoor Air Quality comes from controlling pollutants in building materials and design. 2/3 of dirt in homes is brought in through entryway! Jobsite contamination must be controlled. Materials are constantly being evaluated to provide improvements Environmental Building News October 1st, 2001 Vacuum Insulated Panels Insulation tester – mass buildings Energy Star roofing Efficiency of Evacuated Tube Collectors