— Solar Heated Pool Water – Twin Springs Homestead Research Institute

Ellen decided that in Arizona we should be able to use the sun to heat the pool water and extend the swimming season. This page documents her design and installation. She found suppliers and did almost all of the work with minor assists from Bret and Dave. (*Dave considers figuring out and installing the pump plumbing minor!”)

345_pump_t — Photo shows normal pump plumbing but with a valve added (black) between filter tank and where the water is directed back to the pool.

The pump circulation system needed to be changed for this to work. Shown here, where the filter system was sending water back to the pool, we added a 3 way valve (black) that allows the water to go back to the pool as before, or be sent to the solar panels on the porch roof.

The pipe that leads to the porch roof is the white pipe that goes to the upper right and eventually gets to the black pipe you see on the ground by the wall.
The pool filter/pump system is about 35 feet away from the house (with porch) so the pump has to push the water across the back of the pool along the wall till it lines up with the house. From the wall, the water feed has to go about 25 feet from the block fence to where it rises to the roof.

345_from_pump_1 — The black pipe leaves the pump area and flows along the ground in back of the pool on the way to the solar heaters on the porch roof.

345_from_pump_2 — The black pipe along the back of the pool on the way to the porch roof. (Note the solar oven where solar baked beans are in progress…)

345_from_pump_3 — The pipe turns to run along the back of the house behind the bushes where the pipe rises to get the water to the porch roof.

345_to_roof — More detail as pipes rise from the ground up the house wall to get to the porch roof.

Eventually the water has to get to the solar collectors on the porch roof. There are two pipes in the picture – one taking the water up to the roof and the other bringing it back down. Dave was concerned that the pool filter pump might not have enough oomph to get the water “uphill” and thru the panels, but those concerns were unwarranted.

345_porch_roof — On the porch roof are 2 parallel banks of solar heating panels

The panels on the porch roof are installed in 2 banks of 4 each–the plumbing for 2 banks was not obvious as the banks are fed separately but the supply pipe delivers to both and the returns join together to send the warm water back to the pool. The water is fed at the left side bottom of the collectors and returns from the right side top. A pressure relief valve is installed on the left top corner and an end cap on the right bottom corner of each bank. The panels slant a bit toward the intake to facilitate drainage when necessary.
The cloth straps sent by the manufacturer to tie the panels to the roof disintegrated within 3 months in the Arizona sun! Dave replaced them with plastic covered electrical wire when we found one whole bank of collectors blown off the roof during the summer. Luckily they did not seem to be damaged.

345_PICT0003 — Bret helps install panels in the May sun.

Drilling into the roof is required to anchor the cleats. Silicon caulk is placed over the drilled spots to keep moisture out.

The Internet offered several choices for solar panels to heat pools. They all seemed to use the same basic principle of many pvc black tubes connected by plumbing pipe and rubber tubes with clamps. The main choice seemed to be horizontal or vertical installation. There were also a rather wide range of prices. I looked at: SmartPool Sunheater 2 X 20 Sold in boxes of 2, Aquasol 4X8-4X12, and Harter Hi-Temp 2X15-4X40
The vendor I chose was Doheny’s Water Warehouse for the SmartPool collectors because the installation kit was included with the panels making the total price less than buying an installation kit and separate panels. I had to purchase extra parts though because the panels needed to be installed in two separate “banks”. I had to find the extra parts from a different vendor (PoolSupplyWorld) that sold them separately. I ordered extra roof cleats (that I didn’t need when the missing parts finally came) and a pressure relief valve and got an extra end cap as well as all the connecting pipes (I used ABS pipe because it is black) at Lowes.
One collector box was missing the connecting tubes and roof cleats and it took a couple of months for the missing parts to be shipped. I had not pursued the request vigorously and the company apologized when I had to contact them twice about the missing pieces. The delay caused us to have to wait until the weather got cooler to finish the installation. We didn’t need to heat the water in Arizona’s 110 degree heat this summer anyway and we didn’t miss the nighttime cooling feature that the panels advertise–the water feels good when it is hot even if it is 90 degrees. The low humidity in Arizona cools wet skin rapidly.

When the heated water comes down the second pipe, it falls into the pool. Even flowing quickly, it picks up 10 degrees.

345_ellen_at_pool — After gluing all the pipes and turning on the pump, the warmed water is returned to the pool as Ellen measures the temp.

300_hot_water — The thermometer showing water is 90 degrees. (It started out as 80 degrees before solar warming.)