How I Built a Zero Carbon Footprint House

1. How I Built a Zero CarbonFootprint House Chandu Visweswariah Distinguished Engineer and Senior Manager Timing and Circuit Analysis IBM Systems and Technology Group East Fishkill, NY, USA

2. Zero carbon footprint house built in May 2009; no oil, gas, propane, coal, nuclear energy Summary IBM ResearchYorktown Heights, NY Do not copy without permission

3. Outline • Geothermal heating, cooling and domestic hot water • Photovoltaic solar panels • Other considerations • Conclusions • Outside the scope of this discussion • Global warming and its effects • Energy policy and “dependence on foreign oil” • The frustrations of building a house Do not copy without permission

4. Geothermal intuition • Ever been inside a cavein the summer? • The cave is cool! • During the winter, that same constant cave temperature is warmer than the air outside • The earth is an abundant source of energy at a constant temperature year-round* • In the winter, ground source heat pumps move heat from the earth into your house; in the summer, they pull heat from your home and discharge it into the ground *7oC (45oF) to 18oC (75oF) depending on latitude; 12.6oC (53oF) in New York Do not copy without permission

5. Cold puron Hot puron Hot puron Cold puron Winter Summer Basic idea (one example) Do not copy without permission Drawing courtesy of Prof. Andrew Chiasson, Oregon Instititute of Technology

6. Closed vertical loop • 6 m (20’) bore spacing (7.5 m (25’) in our case),91 m (300’) deep Do not copy without permission Courtesy of Prof. Andrew Chiasson, Oregon Instititute of Technology

7. Closed horizontal loop Do not copy without permission Courtesy of Prof. Andrew Chiasson, Oregon Instititute of Technology

8. Closed pond loop Do not copy without permission Courtesy of Prof. Andrew Chiasson, Oregon Instititute of Technology

9. HDPE pipe Copper pipe Pond loop photos Do not copy without permission

10. Open loop Do not copy without permission Courtesy popularmechanics.com

11. How a heat pump works Compressor Low pressureLow boiling point: gasAccepts latent heatLow temperature High pressureHigh boiling point: liquidGives out latent heatHigh temperature Evaporator Condensor Expansion valve Do not copy without permission Courtesy etccreations.com

12. Enthalpy curves for refrigerants Do not copy without permission

13. System in our basement To radiantzones Zone valves Air handler Heat exchangecoils Heat pump Heat pump Heat pump Do not copy without permission

14. Refrigerant • Direct exchange (DX) • Copper pipes with puron under pressure • More efficient • Allows for domestic hot water • Indirect exchange • Glycol + water mixture (also known as “anti-freeze” or “brine”) • PEX piping • Less efficient Do not copy without permission

15. Properties of Puron • Puron is R-410A, a non-proprietary 50/50 blend of 2 non-chlorinated refrigerants • Azeotropic blend* with negligible glide temperature (0.3oF) • History • 1987 Montreal Protocol • 1990 U.S. Clean Air Act Amendments • R-11 and R-12 (CFCs) phased out 1995 • HCFCs have lower ozone-depleting potential • R-22 (freon) production stopped Jan 1, 2010, phase-out date for existing units 2030 • AlliedSignal/Honeywell invented Genetron AZ-20 (HFC) which was given a generic name R-410A, brand name Puron Do not copy without permission *Same boiling point, so cannot be separated by fractional distillation; same composition in liquid and vapor states when distilled or partially evaporated

16. Puron vs. freon • Higher pressure, lower mass flow, quieter, 31% higher heat-carrying capacity • For more comparison data, see Appendix Do not copy without permission *ODP: a normalized indicator of the ability of a refrigerant to destroy stratospheric ozone molecules referenced to a value of 1.000 for CFC-11

17. Puron enthalpy curves Do not copy without permission

18. Distribution within the house • Forced air works, but radiant is best Do not copy without permission

19. Sub-floor radiant Do not copy without permission

20. Air source heat pumps Mitsubishi Mr. Slim 26 SEER 9,000 BTU HeatPump INVERTER Mini Split System • Recent breakthroughs allow operation at low temperatures, but with lower COPs • No wells, no trenches! • The face of the future? Do not copy without permission

21. Outline • Geothermal heating, cooling and domestic hot water • Photovoltaic solar panels • Other considerations • Conclusions • Outside the scope of this discussion • Global warming and its effects • Energy policy and “dependence on foreign oil” • The travails of building a house Do not copy without permission

22. Average solar irradiance W/m2 • Fastest growing source of energy • 12,400 MW worldwide by year-end 2007 Do not copy without permission

23. Basic physics: light  electricity • Photons from sunlight hit silicon • Some pass through (lower energy), some reflect, some are absorbed (energy > band gap) • These create electron/hole pairs • Pairs that don’t recombine form a DC current • An inverter is used to produce AC current • No easy way to store this energy! Do not copy without permission

24. Stand-offs/mounting Do not copy without permission

25. Inverter (in garage) From panels Inverter Privatemeter Disconnect 8,871kWhrto date To utilitymeter Do not copy without permission

26. PVWATTS • Performance calculator for grid-connected PV systems • http://rredc.nrel.gov/solar/codes_algs/PVWATTS • Inputs to the program • Location (latitude, longitude, elevation) • DC rating of panels (e.g., 5 kW) • DC to AC derate factor (e.g., 0.77) • Array type (fixed, 1-axis tracking, 2-axis tracking) • Array tilt (e.g., 37o for a 9/12 roof) • Array azimuth (e.g., 180o for a South facing roof) Do not copy without permission

27. Type of arrays Do not copy without permission

28. Energy production by month • Assume dc rating=5 kW, inverter derating=0.77, azimuth=180o, pitch=36.9o (9/12), total annual kWh=6,121/7,615/7,840 Do not copy without permission

29. Energy vs. tilt and azimuth • Assume 5 kW dc, inverter derating 0.77, NYC Do not copy without permission

30. Ideal conditions • South-facing singleroof • Solar south* is 13oWest of South • A 9/12 pitch is ideal • No chimneys, poles, trees in the way • In our case • 7.6 KW system • 8,100 kWhr per year average • Eliminates 14,000 lbs of CO2 per year • We have net metering and time-of-day billing Do not copy without permission *Solar south is the angle of the sun at solar noon

31. Outline • Geothermal heating, cooling and domestic hot water • Photovoltaic solar panels • Other considerations • Conclusions • Outside the scope of this discussion • Global warming and its effects • Energy policy and “dependence on foreign oil” • The travails of building a house Do not copy without permission

32. 3. Other considerations • Insulation • Polar walls R-30 (2x8) • Double-fascia roof R-51 • Windows • Double-pane, low-eargon coating • 100% compact fluorescent lamps (CFLs) • Think “passage lighting” during design • Can now use with dimmers! • Transportation alternatives • Use bicycles, carpool, hybrids, electric cars, public transportation… • “Passive power” reduction/instrumentation • Instrumentation is a powerful way to change habits • Reduce, recycle, reuse Do not copy without permission

33. Outline • Geothermal heating, cooling and domestic hot water • Photovoltaic solar panels • Other considerations • Conclusions • Outside the scope of this discussion • Global warming and its effects • Energy policy and “dependence on foreign oil” • The travails of building a house Do not copy without permission

34. Conclusions • We use our geothermal system for heating, cooling and hot water • We use our photovoltaic solar panels for our electricity needs • Net metered, time-of-day billing • Good insulation • Energy-efficient bulbs and appliances • Our investment will be recovered in ~9 years • Technology is available; investment is the issue • We are treading a little softer on this earth • Who knows what the future has in store? Do not copy without permission

35. Imagine? Floating wind turbines The first units in production will be 4 kW residential units that will cost $10,000 Do not copy without permission Information courtesy of Paul Villarrubia

36. Energy from photosynthesis? Do not copy without permission http://www.popsci.com/technology/article/2010-03/video-artificial-photosynthesis-produces-enough-energy-power-house-one-bottle-water

37. Thank you! Do not copy without permission