Solar panels to produce electricity are different from solar panels to heat the pool. The former are quite expensive and convert the sunlight into power to run your appliances, such as air conditioners. The latter are less expensive and produce warm water when the sun’s rays heat up water that is diverted into narrow black tubes.

I have two kinds of solar pool heating devices. The first kind is store-bought, costs about $200, and consists of a 4-foot by 20-foot panel of black pipes and tubes sitting on my patio roof. The principle upon which it works is the manifold. My pool pump pumps water into a “large” tube. The large tube has many narrower tubes connected to it running perpendicular to the large tube. As the water flows through the large tube, about 1/3 of the water is diverted into the narrower tubes. The narrower tubes pick up the heat from the sun. The water runs down the 20-foot length in one direction, and then back to the large tube in the other direction. At the hottest part of the day, the water is returned to the pool at about a 1-degree/hour rise in temperature. The return flow fills up a gallon bucket in 2 seconds. Since my pool contains 4,500 gallons, using a formula, it would take about 2.8 hours to warm the pool by one degree.

The second kind of solar device is homemade, and cost about $30. It consists of two spirals of black ½-inch poly tubing, for a total of about 400 feet of tubing, which sits on my roof. A pump pushes the water through the tubing and is returned to the pool at about a 2½-degree/hour rise in temperature at the hottest part of the day. The return flow fills up a gallon bucket in 15 seconds. It would, therefore, take about 7.5 hours to warm the pool by one degree. It looks like I could use another 600 feet of tubing!

The good news is that (1) I get a thrill each time I realize that my pool is being heated for “free,” thanks to our sun, and (2) that I can “turn off” the solar heaters when the temperature gets too high. The not-so-good-news is that (1) the sun must be out in order for the pool to be heated, and (2) while my swimming season might be extended by a month or two, I do not expect to be able to heat the pool sufficiently in order to swim during the colder winter months.

But, I am having fun calculating the effects of my solar systems. With my pool thermometer in one hand, and my bucket, formulas and calculator in the other hand, I can try to determine just how effective my solar solutions are.

Mr. Ebsen may be contacted at robertebsen@hotmail.com