Latest Technologies

Solar Pool Collectors

Collectors for heating a pool normally do not require glazing or insulation because they operate during warmer months when solar radiation and ambient temperatures are relatively high. This allows for a simpler design that is usually less expensive than collectors for domestic hot water. Many pool collectors are made of heavyduty rubber or plastic treated with a UV light inhibitor to extend the life of the panels. The advantages of plastic collectors are that they’re usually less expensive and weigh less than metal collectors.

Unlike solar domestic water heating systems, which raise a small amount of water to a high temperature of about 140°F, pool heaters raise the temperature of several thousand gallons of water to about 80°F by circulating the water at a relatively fast rate through the collectors. This allows most of the solar energy falling on the collectors to transfer to the pool water. Solar energy not only can be used for heating residential pools but also for larger commercial and public pools.

Metal collectors generally are made of copper tubing mounted on an aluminum plate. The disadvantages of metal collectors are that they are more susceptible to corrosion and freeze damage, and the copper tubes may react with your pool’s chlorine if the pH level falls below 7.2. Too many copper ions in pool water may form dark-colored precipitates, which can coat the pool’s walls. This discoloration can only be removed by draining, cleaning, and repainting the pool. This problem can be reduced if the pH level is always kept above 7.2.

The area needed for collectors to heat your pool depends on many factors. A general rule of thumb is that the collector surface area should equal at least one half of the pool’s surface area. In a relatively sunny climate, this additional heating helps extend the swimming season into spring and autumn. In cooler and cloudier areas, you may need to increase the collectors’ surface area to equal the entire surface area of the pool. Collectors can be mounted on roofs or anywhere near the pool that provides the proper exposure, orientation, and tilt toward the sun.

Collectors can be mounted on roofs or anywhere near the pool that provides the proper exposure, orientation, and tilt toward the sun. The optimum collector orientation is south, but west-facing orientations are good if the collectors’ surface area is increased to at least 75 percent of the pool’s surface area. East-facing orientations are marginally good. The tilt of the collector is as important as the orientation. For heating primarily in the summer, the tilt should equal the latitude where the pool is located minus 10 to 15 degrees. Where optimizing the tilt is not possible, for example on an existing roof with a high slope or on a flat roof, increasing the collector area may be necessary to achieve the desired pool temperature.

One potential benefit of roof installation is that it may reduce the cooling load of the building that it’s located on, since it puts the solar heat into the pool water and keeps it from radiating into the attic and the conditioned space below.