Monday, October 5, 2009

Sunbathing Once Removed - Solar Hot Water and You


The device at left is a self-contained solar hot water heater, featuring panels, mounting frame, and tank at the top. it requires no power for pumps or controls. Water from the tank circulates through the collector plates by convection as the sun heats it, filling the tank with water at whatever temperature the sun can warm it. The tank remains at house pressure, waiting for a demand. At night the tank cools slowly, delivering hot water until the tank is cooled completely.
You can't take a shower at midnight with this rig, unless no one else has used water that evening. You can't store more water than can be held in the tank. You can't rely upon the supply first thing in the morning, or later in the morning, unless the outside temp is so high that the tank doesn't cool much. You can't install this system in a climate where winter temps drop to freezing or below; or, you can't use the system more than five months a year in New England where I live, and it must be drained for the winter when hot water is supplied by another system. You can't supply the hot water needs of an American family of four unless they're all atuned to the daily cycles of water heating and time their use of hot water in zen-like harmonious balance with the (i'm singing now, in a sloppy baritone) "Cirrrrrcle of Liiiiiiffffe." No audio available on that one....
You get the picture? The system shown is not acceptable for Americans. No system I know of is acceptable to Americans, with the exception of aging hippies with dearly held beliefs on the subject. I installed a system several years ago for clients with those dearly held beliefs about energy and independence, but the system nevertheless had to be carefully integrated with a seamless backup, sized to provide hot water for every possible demand including house guests, and separated from the house water supply by a closed-loop heat exchanger filled with antifreeze to prevent freezing. Sporting those features, it cost a small bundle, which federal and state incentives defrayed by over half (here in CT, at the time, state rebates were generous; since then, with a huge budget deficit, those rebates have withered). But it supplies "tempered" (pre-heated) water to their oil-fired backup system on any sunny day in any month of the year, and supplies all of their hot water needs for about six months out of twelve.
That's what Americans require: seamless integration of alternative energy systems into an American lifestyle which forfeits no convenience to the idea of sustainable energy technology. I could sell a lot of the systems shown in the picture; they would supply the hot water needs of a couple for at least the three warmest months of the NewEngland year, saving 25% of the energy costs in a category (domestic hot water) that accounts for at least 30% of an American family's energy bill. Yes; that's 8% of the household's energy costs, defrayed by a system that must be lived with a state of awareness and harmony. No, I won't sing again. The payback period of the system would be about eight years, and it has a life cycle of perhaps 30 years. But all the caveats listed above still apply. You have to live with what the system can do, and what it can't do. How many of my clients are willing to make those lifestyle adjustments? Hands up? I don't see any hands. Guess what? My hand's not up, and I'm an energy-conscious aging hippie and heating/cooling contractor committed to renewables. I'm an American, and I want my hot water without compromise.
There are other solar hot water systems, other designs that contribute to a home's hot water needs in a more American way. This USDE site gives an overview. Costs range from 8 to 25 thousand dollars US to install, and they pay back your investment over periods ranging from ten to 25 years. Do you know how fast they're selling in Connecticut? Not fast at all, especially as the rebates recede and the federal tax incentives age toward 2015, when they will either be renewed or not.
I always plump for low technology, low cost, modest gain energy strategies in this blog and in my business, but I haven't found a way to put solar hot water within the reach of average homeowners yet. The renewables train is coming slowly around the bend, and there's a lot of hemming and hawing among homeowners who'd rather replace windows and siding than invest in solar technology, because that's what's being hawked on the telly. I'm a very modest salesman, with a conscience I wear upon my sleeve, and I can't promise more than the numbers tell me when I talk up renewables. The number are still tough, but they work in the long haul. We need a national, cultural sea change, a tipping point. If it's not on the infomercials, it's not hot. Al Gore can't sell this one: I can't sell this one. The renewables movement is waiting for someone to sell it to America; perhaps only Tom Hanks is up to the job.

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