Opinion –
The Antarctic Swimmer’s Club would likely find little value in solar pool heating. The rest of us, however, might enjoy a swimming pool heated with solar energy.
Although solar heating’s effectiveness had been proven for decades, sales of domestic hot water systems declined in the ’80s for numerous reasons. To find new customers, many solar installers at the time turned to solar swimming pool heating. And still, today, solar pool heating is one of the easiest solar technologies to justify economically. It works throughout the US and Canada, and depending on climatic conditions, will increase pool temperature by about 10 degrees Fahrenheit.
Most American swimming pools are solar prospects-in-waiting-heated with natural gas, propane, or electric heat pumps. And commercial opportunities abound, from hotels and resorts to apartment complexes, health clubs, parks and schools; many of which need to maintain comfortable water temperatures.
Unlike other solar heating technologies, solar pool heating is ineligible for the federal energy tax credit. The inside scoop is that congress doesn’t want to give the tax credit to what they see as a luxury item. But even without the incentive, the economics work. Some states require a licensed plumber or other certification, thereby offering plumbers a strategic plus.
Costs
Obviously any swimming pool heated with natural gas, propane or electricity is costly, and therefore justifies the cost solar pool heating. A hybrid system-one that employs an existing heating system as a backup to the solar heating-is especially cost effective if the fossil fuel system is already in place. For year-round pools, such a hybrid system can cut the cost of fuel in half for the year. And for seasonal pools, 100 percent of warmth can come from the solar heating.
Since there are many variables in costing a solar pool heating system the payback time from the reduced energy use can vary widely, from as little as one year to as many as seven. For one thing, local fuel prices vary from region to region. Different climates warrant different technologies. Typically a solar pool heating system will last longer than gas and heat pump pool heaters, which only adds to solar’s value. Expect the system to last between 15 and 20 years, although some may last longer. For pools without any installed heating system, the “savings” comes in the extended use of the swimming pool during cooler seasons.
How it works
The solar pool heating system’s simplicity is the reason for the low cost and swift payback. The system pumps the pool water through a filter and then through the solar collectors. In the collectors, the water is heated by the sun, and then returned to the pool. You can think of a solar pool heating system like the water in a garden hose warmed by the sun.
Most solar pool heating systems are made of four components that will certainly be familiar to tradespeople. The solar collector; a filter; a pump; and a flow control valve. Typically, pool heating uses an unglazed collector to absorb heat from the sun. Glazed collectors are more expensive than unglazed, but may be necessary in colder weather. Glazed systems typically employ heat exchangers and transfer fluids and can be used year-round in many climates for heating water.
The solar thermal industry is segmented by the temperatures the systems can achieve. Glazed collectors are in the middle range of the temperature scale, and create domestic hot water at about 120- to 160 F. Unglazed collectors are at the lower end of the temperature scale and best used for pool heating when temperatures are above freezing. Although unglazed could work for indoor pools in cold climates if the system is designed to drain back to the pool when not in use. Unglazed collectors don’t have a glass covering, or glazing. Instead, they are generally made of heavy-duty rubber or plastic treated with an ultraviolet light inhibitor to extend the life of the panels.
Polypropylene is a common material used for unglazed collectors because of its resilience against physical damage and freezing. Polypropylene is a material commonly found in auto parts and food containers.
System design
When designing a solar pool system, consider several important factors. Most importantly, the system efficiency depends upon how much of the sun’s energy reaches the collectors. Either direct or diffuse light will heat water, but mount panels away from shady areas. The system size should account for the amount of thermal energy needed to heat the pool. Therefore, pool size, average regional climate and preferred pool temperature are part of the equation.
Hybrid systems offer a reasonable balance between energy savings and initial cost for systems already heated by natural gas, propane or electricity. As the installer, demine the contribution of heat to come from the solar collectors. You’ll want to know the efficiency of the heating system – a thermal performance rating usually measured in Btu (British thermal unit) per square foot per day; the higher the number, the greater the solar energy collection efficiency.
Solar pool heating systems are simple and affordable. And usually no special maintenance is required. But there is one trick you’ll want to remember for early morning swims when taking a dip out of season in a solar heated pool; cover the pool at night to trap the solar heat that was gained during sunlight hours; although Antarctic Swimmer’s Club members will be fine ether way.
[...] OptionOptions Available in Oval Above Ground PoolsHome Solar 101: A Homeowner's Guide to SolarSwimming in Solar-Heated Water: An Overview of the Solar Pool Heating Market body.custom-background { background-image: [...]