Harness the power of the sun
Passive thermal solar systems typically utilize the existing swimming pool circulation pump to send water through a series of solar collectors—mounted on the facility’s roof or on a ground-support system—where heat is transferred from the sun to the pool water.
Downstream of the pool filtration system (but upstream of the pool heater), a bypass piping system is installed to route the pool water into the solar collectors.
When used in conjunction with a commercial pool heater, if the solar heating system can provide the necessary set point water temperature, the pool heater will not operate, thereby reducing its run time and associated natural gas costs.
Over the decade, commercial swimming pool operators have expressed a great deal of interest in solar heating systems. With utility rates spiking over the last few years, this interest has increased. Back when natural gas had a unit price of $0.55 per therm, proposing solar was less likely due to the eight to 10-year ROI and the average system’s 12-year life span. More recently, however, with natural gas prices hovering in the vicinity of $0.85 per therm, ROI can now be realized in four to six years, which is considerably more attractive to the average pool operator.
Of the systems studied, copper and glazed solar panels are the most efficient. However, these systems are less than ideal for commercial aquatic facilities due to the high potential for vandalism (e.g. kids tossing rocks and breaking the glazed panels). In addition, the high potential for imbalance pool water chemistry can wreak havoc within copper piping.
For example, if the pH feed system were to malfunction and drive the pH below seven, copper could precipitate out of the solar heating system and into the pool water, thus discolouring plaster to the point where it might have to be completely replaced.
For these reasons, the use of non-metallic solar panels (typically polypropylene [PP] or ethylene propylene diene methylene [EPDM] collectors) are preferred. These systems are less expensive than copper and glazed solar panel varieties and installation costs run approximately $12 to $18 per square foot (assuming suitable mounting space with proper solar orientation is available).
The amount of solar panels required varies greatly by region, but an average of 80 per cent of the water surface area is common for all but the most solar-challenged spots within North America.
For example, a 50-m (165-ft) outdoor commercial pool, would require approximately 929 m2 (10,000 sf) of solar panels, with installation costs ranging from $120,000 to $180,000. However, with a potential annual operating cost savings of $50,000 to $75,000, a passive thermal solar heating system can be an attractive option for many pool operators.
See the light
Another way to reduce an aquatic facility’s energy costs is to replace energy-consuming incandescent underwater lights with high-efficiency LED fixtures. They produce approximately the same amount of light as a 450-watt incandescent fixture, but provide energy savings of nearly 85 per cent.
Initial capital costs for LEDs are approximately double the price of incandescent lighting; each fixture costs approximately $1,000. However, an LED fixture will provide close to 50,000 more hours of light compared to its incandescent counterpart.
