JohnRoss Posted July 7, 2009 Share Posted July 7, 2009 Just thought I would come back and report on my el cheapo solar heating system. Extended my black painted, blackboard paint from Bricomarché, 100mm plastic pipes laid out in the field giving a total run, mostly East West, of 260 metres. Gives a total heat pickup area of about 50% of the pool area. Pool 5 x 10 metres by Desjoyaux, approx 75 cubic metres. Making the assumption that just under one third of the pipe circumference picks up significant amounts of heat. The summer cover was kept on most of the time so reduced direct input into the water.Tried various flow rates and the best flow rate/temperature rise product was at 54 litres/min, a small proportion of the flow through the pump, giving a typical rise of 5 to 6 degrees between input and output. Other flow rates tried were 36, 27 and 15 litres/minute.The pool has been too hot of late, maximum noted 34 degrees, and I had to run the pipes at night from time to time to get it down to 30 degrees. Lower flow rates gave a greater rise in temperature, 9 degrees at 15 litres/minute, between input and output but a lower flow rate/temp rise product. I have nearly always run them during the day even if the pool did not need heating as to leave them siting in the sun without flow produced in-pipe water temperatures of up to 45 degrees. Don't know how long they would stand that. I think pool temperatures in excess of 30 degrees might shorten the life of the liner. Current pool water temperature today of 29.5 degrees. On balance an experiment worth doing I think but some may not agree.............................................................JR Link to comment Share on other sites More sharing options...
Théière Posted July 7, 2009 Share Posted July 7, 2009 Correct JR, I think it's an experiment not worth doing unless you get a rise of 5 to 6 degrees in April/May or September/October, who wants a very hot pool when it's 45 degrees in the sun? My Pool was 28 degrees without any form of heating coil etc. Link to comment Share on other sites More sharing options...
JohnRoss Posted July 7, 2009 Author Share Posted July 7, 2009 It was certainly 5 degrees rise at the solar peak in mid May and at the maximum flow rate. There is evidence that pipe length extension follows a law of diminishing returns supporting the idea that parallel fed systems may be better but more expensive of course........................................JR Link to comment Share on other sites More sharing options...
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