Solar heating with PEX

[bfrisch]

I have seen a few other posts about how this is probably a fruitless endeavor. I have a 16'x32' 14,300 gallon saltwater Intex AGP and I am trying to heat it up 5-10F. I have a pool cover and that has been getting it up to the mid 80s with the high ambient air temp in the low to mid 70s, but I want to get the water temp into the 90s. I was thinking about building a secondary pump system that did not drive off of my main filter pump, run it through a few hundred feet of PEX tubing and use heat spreaders that are used for radiant floor heating, paint it all black and cover it with greenhouse plastic sheeting, and set it up along the south edge of the pool. I am thinking that this DIY setup will run me probably about $600 for plywood, pump, tubing, plates, etc. plus the electricity to run the pump when desired. I don't think I can run it to the roof and I am in the process of getting solar panels anyway which would mitigate the cost of electricity to run the pump. I saw a YouTube video of someone doing something similar with copper tubing in a single circuit and got the water temp to near boiling. I want multiple circuits of about 100' instead of one very long circuit because hot water only absorbs so much heat. I can't use copper due to saltwater. If I do 4 sheets of 4'x8' plywood that would be a total area of 128 sqft vs 512 sqft of pool surface area so only 1:4 instead of the recommended 1:2, but I am hoping for more heat transfer.

 

[proavia]

I can't use copper due to saltwater.

Lots of pool owners have heaters with copper heat exchangers and they also use a SWCG without issues.
All pools are salt water pools - chlorine and acid adds salt to the water. After several years, a non-SWCG pool can easily have over 2000 ppm salt.

Have you looked into purchasing a few pool solar panels and ground mounting them?
Might be easier and likely more efficient than a home-grown solution.

 

[magiteck]

I’ve been really pleased with this panel for my pool:

FAFCO Super Solar Bear Above Ground Pool Heating System with Installation Kit 10061
Amazon.com

I live in east-central Wisconsin, where we’re not exactly known for our warmth, and I’ve had my pool as warm as 92 this Summer.

Here’s a pic where you can see the ground rack I built for them:

D0205F8C-C0E6-4622-86A2-BE77827BCA48.jpeg

• magiteck
• May 15, 2022

 

[VinnyinNJ]

Getting a pre made solar panel is probably the best way to go but I saw a YouTube video where the guy built a solar heater out of black irrigation hose.

Nothing fancy, just a coil of hose, a square piece of plywood, a couple of 2x4s, I think a fitting for the pump and the pump. Per his video the water was coming out pretty warm and he could move it out of the way when needed. Per his viewers he could have made it better by putting sides on the plywood, painting the housing Matt black and putting a plexiglass cover on the whole thing. Doing all of that would have made it much heavier to move IMO.

Our water has been hovering in the 82 - 84 degree F range and it was 92 F last night with just the solar cover. I was thinking of making that heater to get a little extended range but it may never happen.

 

[bfrisch]

Lots of pool owners have heaters with copper heat exchangers and they also use a SWCG without issues.
All pools are salt water pools - chlorine and acid adds salt to the water. After several years, a non-SWCG pool can easily have over 2000 ppm salt.

Have you looked into purchasing a few pool solar panels and ground mounting them?
Might be easier and likely more efficient than a home-grown solution.

Okay, revisiting the copper approach - cost prohibitive which is not surprising. Probably run my estimates up to $1k for the project if not a bit more.

I guess the original question is really - can I build a better, more reliable solar heater than I can buy for the money? Hearing about someone having a leak and losing half their pool water is a bit scary. Even with solar panels I will likely need a secondary pump to run it because 1. fear of burning out my filter pump, and 2. the location of the filter pump is not convenient for solar heating so I would need at least 15-20' of tubing to get around the pool to the solar panels.

 

[1poolman1]

I have seen a few other posts about how this is probably a fruitless endeavor. I have a 16'x32' 14,300 gallon saltwater Intex AGP and I am trying to heat it up 5-10F. I have a pool cover and that has been getting it up to the mid 80s with the high ambient air temp in the low to mid 70s, but I want to get the water temp into the 90s. I was thinking about building a secondary pump system that did not drive off of my main filter pump, run it through a few hundred feet of PEX tubing and use heat spreaders that are used for radiant floor heating, paint it all black and cover it with greenhouse plastic sheeting, and set it up along the south edge of the pool. I am thinking that this DIY setup will run me probably about $600 for plywood, pump, tubing, plates, etc. plus the electricity to run the pump when desired. I don't think I can run it to the roof and I am in the process of getting solar panels anyway which would mitigate the cost of electricity to run the pump. I saw a YouTube video of someone doing something similar with copper tubing in a single circuit and got the water temp to near boiling. I want multiple circuits of about 100' instead of one very long circuit because hot water only absorbs so much heat. I can't use copper due to saltwater. If I do 4 sheets of 4'x8' plywood that would be a total area of 128 sqft vs 512 sqft of pool surface area so only 1:4 instead of the recommended 1:2, but I am hoping for more heat transfer.

A ninety-degree pool (near bath temp) will have a huge chlorine demand. Just be aware.