Take the 2-minute tour ×
Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

Background: Late in the summer last year I finally commissioned a DIY solar hot water pre-heat project. Very simple, drain back, open (vented) tank, PEX coil for a heat exchanger, PEX plumbing throughout, panel is about 10x12' with re-purposed aluminium "staple up" radiant floor transfer plates. Anyway, long story short, the performance has been disappointing, bottom line is that the storage tank temperature has never really exceeded 25°C. On the other hand, despite being in an unheated crawlspace in Halifax, over the winter it never was below 15°C, either, so its better than nothing (better then the cost of the pump, I haven't calculated). I suspected the solar controller, or rather, its analogue probes, of being a problem, and finally got around to installing a bunch of digital probes and flow meter (raspberry pi).

After a day of monitoring, its clear the flow is right at 15 l/min. I just now repaired some more wiring, and will update tomorrow with some sample temperature of the panel, tank, and return water.

share|improve this question
2  
Got any pictures of your setup? it's not clear. Sounds like most of the issues are in your solar collector. –  Matt Jul 22 '13 at 21:56

2 Answers 2

Are the PEX hoses black and is the sun side of the re-purposed aluminum plates black?

If not you may want to consider changing this so as to increase the efficiency solar energy absorption.

share|improve this answer

PEX is not a good material to transfer heat. Consider the ideas in this article:

http://davidmdelaney.com/solar-water-heating.html

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.