Siting a Solar Pool Heater
Siting the solar pool heater collectors for your pool is very important. Collectors can be mounted on roofs or in other locations near the pool that provides proper exposure, orientation, and tilt towards the sun. The optimum collector orientation is south, but west-facing orientations are acceptable for pool heating as long as the collector area is increased to a minimum of 75% of the pool surface area. East facing orientations are to be avoided.
Prior to siting a solar pool heating system a shading assessment needs to be conducted that documents the effects of permanent and seasonal shading on the proposed array location. The site’s monthly and/or annual percent shading impacts from each solar shading study should be recorded. (No shading = 0%, Site is fully shaded = 100%)
The tilt of the collector is just as important as the orientation. To receive maximum solar radiation, collectors should be perpendicular to the sun’s rays. For primarily summer heating, the tilt should be equal to your latitude minus 10 to 15 degrees. In situations where it is desirable to install the collector horizontally, such as on a flat roof, the collector area should be increased to 75% of the pool surface area.
The solar pool heating system is optimized by siting the collectors where there is little to no current or anticipated shading. Shading is an important factor in determining a site’s suitability to support a solar energy system. A solar site assessment study helps to ensure that permanent and seasonal shading impacts are accounted for under actual site conditions.
A Solar Pathfinder, Solmetric SunEye, or an industry accepted equivalent can be utilized to conduct the shading assessment. This sunpath tool is used to determine the seasonal shading impacts on the proposed collector location.
The solar shading assessment should determine the percent of available solar radiation (or conversely the percent shading impact for the proposed collector location) on a monthly and/or adjusted annual basis. The estimated shading impact will contribute to a system output derate factor, which will affect the site’s suitability to support a system.
In the event that the proposed collector location is large in square footage, or is divided between two different roof planes, then multiple shading studies should be conducted at various points across the proposed area(s). Siting a solar pool heater should be done with care.