controller for pool solar heater

Hi to all This is my first post here.
I am a complete novice and I am after some advice on a project im considering.
I have an above ground swimming pool (15,000 L) that I have hooked up to a 20 meter square solar heating system mounted on my shed roof,
The heating works great but I am suffering heat loss through the system when its not so sunny. The joy of a British summer.
I run the pump on a timer from 9am to 6pm I want to be able to monitor the pool temperature and the water temperature when passthrough on the solar heater.
I have a 3 way vale fitted to the 36mm feed pipe to the solar heater. picture attached but here is a link
to the valve.

which I want to be able to adjust to restrict flow through the solar heater to optimise heat gain. I have looked at
solenoid valves but I am thinking that resticting the flow is a better option than just a simple on/off.
Any ideas on a suitable replacement 36mm 3 way valve that would work or could i fix a motor to the existing lever to do the job.
Thanks Steve

3 way.jpg

a motorized valve would offer some help.

what would consider is a solar pump. pump speed = power available. more sun, more heat, faster pump

but, you have a much larger heat exchange issue. evaporation will cool the surface overnight unless you cover the pool

also, BTU is not really dependant on flow rate. there is a sweet spot on harvesting heat. run the water too fast, the pipe gets too cool and condensation cools more than you reap. too slow and the water stops getting hot.
heat exchange is most efficient with the widest extremes. it is easier to increase temperature by 10 degrees if the starting point is 50 degrees off. much harder to increase by 5 degrees when the starting temperature is 10 degrees off.

we had a blow up pool when the kids were young. first year could not get it warm.
second year, put down an inch of sand, then a layer of foam store bought insulation 1/4 inch.
it got warm and stayed warm. the heat loss to the ground was excessive.

Many valves support proportional operation (by PWM signals), not only on/off. You need a valve data sheet anyhow, for connecting the item to your controller, so find the data sheets before you consider to buy any components.

google arduino solar pool controller

Looks like good project for the arduino.

What do you do during winter, does your pool and hence will your solar collector freeze?

Tom... :slight_smile:

Hello Steve,
I am doing almost the same as you are doing .
I also bought a simple 2 way valve and I motorized it myself .
I wil attach a picture this evening or tomorrow .
I used a 2 way valve because I think this is OK : if the filterpump is running and the valve is open , the water takes the easy way direct to the pool . If the valve is closed it can not go direct to the pool and it has to go to the solar collector .


Difficult to see on the picture because it is build in already .
It consist out of :

  • 2 way manual vale
  • gearmotor 12 V DC
  • 2 NC proximity switches
  • 2 ch relais board 12V DC