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Old 10-13-11, 02:55 PM   #1
Daox
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Default DIY Solar hot water heat exchangers

I'll be working on my solar hot water setup quite soon and am thinking about heat exchangers. It seems like data to help you size a heat exchanger is next to non-existant online, so lets put some together.

I love Gary's 300' of 1" pex that he uses for his hot water setup. Its simple, and works great. However, mine will be used for more than just DHW. It'll also be used for space heating. In Gary's testing, he shows that at higher flow rates, the PEX can not keep up. So, I'm looking for something a bit beefier. Some thing that can exchange heat a bit faster. I don't have my house all on hydronic heat yet, but that is the plan so I will design with that in mind.

The initial thought was a spool of copper tubing. Copper conducts heat faster than pex. So, run a few lines in parallel to reduce pressure drop and you have a nice heat exchanger. Make the lines relatively small to ensure good heat transfer. The problem here is copper is expensive. However, I think I'm going to at least need to use some copper to make this work.

Anyway, I'm looking for any help here. Any tips to make a good heat exchanger that can handle moderate flow.

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Last edited by Daox; 10-13-11 at 03:40 PM..
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