I just dropped the price of
the permaculture playing cards
for a wee bit.



uses include:
- infecting brains with permaculture
- convincing folks that you are not crazy
- gift giving obligations
- stocking stuffer
- gambling distraction
- an hour or two of reading
- find the needle
- find the 26 hidden names


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Using air as a heat transfer fluid for heating water?  RSS feed

Erik Lee
Posts: 104
Location: Zone 6 - Missouri
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I'm working on a design for a solar dehydrator that I'm hoping will get closer to 24 hour operation by storing heat in a water tank, and as part of that design I'm trying to get at the best way to handle heating the water. I've seen some stuff about using air as a heat transfer fluid (basically the solar panel heats the air, which then flows up into a heat exchanger in the water tank and heats the water). That is very attractive to me because of the freeze resistance and simplicity. I was wondering what kind of other problems might crop up as a result of taking that approach though -- would efficiency be lower, how does it perform in less-than-perfect conditions, etc? Are there any major gotchas for using air as the heat transfer fluid in a water heater?
Bob Ramlow
Posts: 34
Location: Amherst, Wisconsin
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The problem that will happen is that when it gets below freezing outside the cold air will freeze your heat exchanger. I do not suggest using air collectors to heat water. Liquid type flat plate collectors are reliable, not that expensive and are easy to use in a freeze-proof system.

He's dead Jim. Grab his tricorder. I'll get his wallet and this tiny ad:
The $50 and Up Underground House Book by Mike Oehler - digital download
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