Quote:
Originally Posted by CanisLupusArctos
How hard would it be, or how much would it cost to hook up electric heat to some solar panels? Or at least enough solar panels so that the cost of running the electric heat was less than heating with oil.
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According to Wikipedia ( I don't have this stuff on the top of my head), solar input energy at the equator on a sunny day is about 1000 watt/square meter. Typical photovoltaic efficiency is said to be 12% currently (getting better with time). Average recovery of juice from a panel in southern US, given typical weather/cloud cover, length of day, totals about 1 kwh/m2/day.
For a house presumably of typical construction (meaning thermally quite leaky) in the northeast in the dead of winter, let's suppose the (electric) heating bill is $600/mo. At 12 cents/kwh, that comes to 5000 kwh/month, or 167 kwh/24 hour day, 6.94 kw average rate, which equates to an average loss of almost 24,000 BTU/hr. That's average, and not for large house, either. Peak loss could be double easily.
To provide that energy with PV panels, assuming some battery to store juice for night use and inverter to boost the voltage, that 167 kwh would call for 167 square meters of panels, or about 1800 square feet. It wouldn't really fit on the roof, being, say, 36x50. Actually, being in the northeast, it would have to be considerably larger, given the lower solar intensity. I hope I haven't screwed up the calcs, but I think you get the idea of the surface needed.
A more workable solution would be to use the surface for solar hot water heating. More energy can be recovered per square meter of area as heat than as electric power. The heat can be stored in a large insulated tank in the basement and circulated through the house as required, through the night. This "battery" wouldn't have to be replaced every few years, either.
Before folks think about "green" ways to provide energy for domestic use, they ought to think more about the very "ungreen" energy demand of the house itself. Almost any house built with typical construction techniques can be improved thermally to reduce its energy demand. Anyone contemplating building new really ought to spend some time on the Internet exploring how to do it right, and not depend on some "builder" to know what to do. Most don't have a clue when it comes to building energy-efficient houses, although a few have become good at it and more will over time. But then, most homeowners haven't a clue either, being more willing to spend money on granite countertops, home theater rooms, and outside hot tubs than on the building shell that keeps them warm in winter.
[Ah, I'm soap-boxing again. Gotta cut this out]