3.3.2 SOLAR POOL HEATING

An unheated swimming pool has a natural yearly temperature cycle that varies with climate and geography, which in most parts of the world limits outdoor swimming to just the summer months. However, a comfortable three to four month swimming season can be stretched out to five or six months when a pool heater is added, even longer in warm climates, as shown in figure 3.7.

 

Source CRES-TRASOL CD-Rom
Figure 3.7 Solar pool heating system

While heating the pool can enhance the enjoyment of the pool, the cost of keeping all that water warm is very high. However, if proper advantage of the strong summer sun is taken, then those high heating costs can be reduced while still obtaining the benefits of a warm pool.

A swimming pool requires low-temperature heat to maintain the water temperature at a minimum of 24°C and, preferably, at 27°C. The small difference between the average daytime temperature of an unheated pool and the desired temperature for swimming allows the use of very simple but efficient collectors, very similar to bare plastic hoses. Such systems require no separate storage tank, since the pool itself serves as storage. In most cases, the pool's filtration pump is used to push the water through the solar panels or plastic pipes. When adequate sunshine is available, the filtered pool water is circulated through the collector tubes, where it is heated by the solar radiation and then returned to the pool. Circulation of all water through the filter about once every 8 to 12 hours is recommended.