It is possible to go all electric, even in MN, but it requires different house construction. Bob Ramlow lives in Wisconsin and says his solar hot water provides about 70% of his heating requirements. His book, Solar Hot Water Heating, describes (among other systems) using solar hot water collectors to heat a 2 ft thick layer of sand which is insulated inside the house foundation with a concrete slab floor on top of it, giving over one hundred of metric tons of thermal mass for radiant floor heating. Water is circulated through the sand with PEX tubing, starting around mid August to heat it up for the winter. With such a large heat capacity, the temperature of the mass decreases only a little over a span of several days of cloudy weather. This, with something similar to passive house design - eliminating thermal bridges and "wrapping" the house in high R value material - would likely permit meeting heating requirements in all but the more extreme stretch of very cold days. Re-insulating an existing house is far more difficult though since it is almost impossible to eliminate all thermal bridges due to the house construction.
Air source heat pumps such as the Fujitsu 12RLS and Mitsubishi FE12NA have greatly improved over the last 10 years or so, operating down to as low as -20F, and offering COP values of 2 - 3 for -5 F < outside temperature < 30 F. This was posted by a person who lives in Newfoundland: "With regards to residential space heating, as noted before, our forty-four year old, 232 m2 Cape Cod is heated by two air-source heat pumps and last year their combined usage came to 3,829.7 kWh (and bear in mind our winters in this part of the great white north are even colder than those of Buffalo, NY). I should also point out that had we opted for best in class performance, i.e., the Fujitsu 12 or 15RLS2, we could have theoretically cut that by an additional 1,000 kWh." So less than 3 MWh with the better heat pumps. This would be over maybe 170 heating days, or about 18 kWh/day on average? Energy use could be greatly reduced with a better insulated house than the old Cape Cod. -- View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/Re-EV-Demand-Response-now-Home-solar-tp4673400p4673425.html Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com. _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
