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Solar Evacuated Tube Ideas for Hot Water (Read 4953 times)
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Solar Evacuated Tube Ideas for Hot Water
Apr 13th, 2011 at 9:47am
I was watching Dan's video where he uses a Solar Evacuated Tube to boil some water.


We know at noon the sun is about 1000W per sq. meter (about 3ft. X 3ft) so you have a lot of power there.

Get one of those tubes and pass a copper tube through it, if you want, fill it with grease (for thermo conductivity), use a grease gun to pump it full. Get a little solar pump going and you are all set for free hot water!

No wait, just put a coating of grease on the copper tube on the sun side only and push it against the front with some type of end caps so it contacts the front surface all the time, that should do it.

End caps ideas may be: rolled up aluminum cans, stuff it with steel wool?

The grease I've tested for thermo conductivity is a high temp disc brake wheel bearing grease, with aluminum and molybdenum added, you can get at any auto parts store. It works pretty good, almost as good as the white zinc oxide based stuff that's very expensive.

2 hours to boiling water he said!

Better put a thermo switch on it. There has to be places selling those somewhere. They are like little button switches, like about the size of a nickel with two leads coming off, very simple to use, the temp is pre-set.

If you use hot water rated PEX (plastic) tubing leading to it you probably wouldn't have to worry about it freezing.

Would be good to lower the electric bill on a hot tub or possibly for a hot water heater application.

Ideas? Links?
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