278. ZERO ENERGY HOMES
Expanding on Rembrandt's excellent post about the future of housing, I'm going to continue digging into new (and old!) techniques for energy self-sufficient housing. This is an important topic because we often hear bloated doomer estimates of how much gas, coal and nuclear we're going to need to keep our civilization afloat. If housing can be retrofit and redesigned to minimize/eliminate the need for electricity and heating fuels, we're going to be well on our way to a bright future.
The DOE (U.S. Department of Energy) has a great website packed with information on energy efficiency. I'll be exploring this site further in upcoming posts, but today I would like to discuss some experiments the DOE has done on "Zero Energy Homes".
Now, the term "Zero Energy Home" (ZEH) is a bit of a marketing term, and does not necessarily mean a home requiring zero grid energy. It is, however, a very good start, as can be seen in the pdf "On the Path to Zero Energy Homes". This pdf describes research conducted by the DOE in Florida in 1998 using a ZEH and a control home:
The ZEH has a variety of efficiency features, both in terms of architecture and equipment: a 3-foot roof overhang for better shading, a reflective white-tile roof, better outer wall insulation, interior-mounted ducts which don't pass through the hot attic, solar control windows, high-efficiency appliances and lighting, programmable thermostat, solar water heating system, downsized air-conditioner and a 4kW PV (PhotoVoltaic) solar panel array.
In testing, the ZEH performed nicely:
When all the numbers were in, the Zero Energy home performed extremely well. The results for June 18, 1998—a day with the hottest daytime temperatures ever recorded in Lakeland, Florida—tell the story. During a 24-hour period, the Zero Energy home used 72% less power from air-conditioning than did the control home, despite the fact that the occupied Zero Energy home maintained cooler indoor temperatures.Here's the graph (the original itself is a little blurry):
The yellow line indicates electrical demand of the control house; the red line indicates power produced by the solar array of the ZEH; and the blue line indicates net electrical demand of the ZEH. As you can see, there were numerous times -- during the hottest day on record in Lakeland, Florida -- when the ZEH was supplying electricity to the grid, not taking electricity from it.
This is very interesting for two reasons:
- It shows that Jim Kunstler's gleeful forecasts about the death of Phoenix/Las Vegas due to lack of air-conditioning are unfounded hype.
- More broadly, it shows how we can greatly reduce -- and maybe even eliminate -- the need for fossil/nuclear power plants, as well as centrally distributed fuel oil and NG. And if we can do that we're going to free up a sh*t load of fuel and nuclear capacity for more important tasks.