Tiny pool, solar panels, is the pump too powerful?

[Amy-CA]

We just upgraded to a 1 HP pump and new cartridge filter for the AGP. Now the water is SWOOSHING through the solar panels so fast, it seems it will never be there long enough to get warm. Is it possible and recommended to slow the flow of water going to the panels on the roof with the ball valve or will that burn out the pump motor?

2750 gallons, two panels (80 sq ft) on the 1-story roof with 1-1/2” feed and return lines. The pump is a 1 HP Hayward Power-Flo LX, the cartridge filter is a Pentair 75 Clean and Clear.

 

[Donldson]

Counter-intuitively the best use of a solar heating system is to run the pump fast enough that the water exiting will have as little temperature change as possible. This is the most efficient way to do it because the water takes every bit of heat it can out of the solar collectors before that heat can be absorbed by the air instead. Remember: your goal is to heat the pool, not just the water in the solar collector. So the temperature of the water coming back in to your pool is less important than the total amount of energy being transferred.

So unless the increased water flow is causing leaking you want to keep it the way it is. And since I haven't said it yet: Welcome to TFP!

 

[Amy-CA]

Thank you Donldson. Counter-intuitive indeed. No leaks! But the temp of the water coming back into the pool seems to be the same as the temp that is going out. Shouldn’t the return be a little warmer? And thank you so much for the welcome!

 

[Andrew_D]

It should be slightly warmer, but I suppose if the water is super fast, you may not notice the temperature increase.

Another option would be to plumb a bypass so that you can run the pump and filter without the solar panels. If you had that, you could crack the bypass valve slightly. That would provide less water to the panels.

Andrew

 

[Amy-CA]

thanks for that suggestion. We do have a bi-pass valve on the wall going up to the panels. Maybe that would work to limit the flow a little. Don’t want to overwork the pump. Donldson suggested wide open. There IS warmer water coming in now and the pool is up 3 whole degrees since this morning. It will be some experimentation. Thanks again!

 

[Andrew_D]

No idea what your sun is like there. But I bet it's a lot more than mine up here! I usually run my solar 8am-8pm. At 8am, the water coming out starts off hot, so I know the panels have already absorbed some heat. But after running 5min, the water coming out is almost the same temp as going in. 3pm is a different story. But there is still a little gain, and I need all I can get up here!

Andrew

 

[Pool_Medic]

Think of solar in this manner, you’re not trying to heat the water, you’re trying to cool down the panels. The bonus is you get warmer water.

 

[Amy-CA]

Think of solar in this manner, you’re not trying to heat the water, you’re trying to cool down the panels. The bonus is you get warmer water.

Ahhhhh, I do love a bonus. UPDATE: pool temps went up about 9 degrees yesterday to 75. We have southwest facing, sun-drenched 1 story pitched roof. I think the panels are doing what they are supposed to do and we keep the water snuggled in a solar blanket at night. Thank you everyone for your guidance and advice (and encouragement).

 

[Amy-CA]

No idea what your sun is like there. But I bet it's a lot more than mine up here! I usually run my solar 8am-8pm. At 8am, the water coming out starts off hot, so I know the panels have already absorbed some heat. But after running 5min, the water coming out is almost the same temp as going in. 3pm is a different story. But there is still a little gain, and I need all I can get up here!

Andrew

I saw a lot of DIY videos from our Canadian neighbors. You are not alone in the desire for a pool. I think the temps go up a teeny bit as the day wears on. A slow but sure pace. Wetsuits are on sale... I considered a new one for the winter months.

 

[Andrew_D]

Wetsuits are on sale... I considered a new one for the winter months.

We use ice skates in the winter.....

Andrew