Pool heating with homemade solar thermal
Not sure if this is officially on topic, so correct me!
Last year we made a couple of pool heaters from irrigation piping, some wood and a flood pump. The total length is around 300m of pipework which sits on a cabin and it works like a charm. We are currently heating a small pool (3m x 1.5m) and we've got it up to 27°. Current return temp is 35°. Last year we got the pool up to 36 and it was basically a hot tub.
Consider it just works by getting warm in the sun, it's excellent. Zero maintenance, no parts to change - warm pool for free (or a small amount of you need to pay to run the pump).
For anyone interested there are loads of YouTube videos on solar Pex coils. Some people even use them in a residential setting to lower heating costs via pre heating.
This is actually a subject on which I have been doing some research for quite some time, not for pool heating since we don't have a pool, but more importantly to store thermal energy for later use. I actually built a small test rig using a 4 pint milk container and a piece of 15mm copper tube, with which I managed to heat 2 litres of water up to 40C using just solar energy.
It is part of a design I have been developing, that would store energy in a quantity of water during daytime, and then use this stored energy to preheat the air being drawn into an ASHP when the temperature falls to +5C or below at night. In this way it should be possible to maintain the efficiency of an ASHP for longer and hence improve its overall efficiency.
Anyone who would be interested in more details then please get in touch.