How Much Do Swimming. Pool Covers Help?

An opaque or transparent swimming pool cover

— which will transmit solar radiation to the water

— can give your pool another 10 degrees of natural storage capacity. This means that if a free-floating cover with pockets of trapped air is stretched over the pool at night (and whenever no one is swimming), we can expect the water temperature to stay at up to 20 degrees above the surrounding air (Figure 94).

Insulating "pool blankets," as they’re called, pass about 85 percent of the light that hits them through to the water. Some are even mounted on convenient reels, which let them be stretched out and rolled up again without a lot of hassle. Ideally, of course, a pool cover should be custom-fitted around the edges, so there’s an absolute minimum of heat loss resulting from evapora­tion, re-radiation and air convection. (A wall, hedge, fence, or wind screen around the perime­ter of the pool, by the way, is another potential heat — and money — saver. This will help to keep passing wind from robbing heat from the water.)

Подпись:Подпись: One of the finest insulating pool covers is manufactured by LM Bearing Associates, 12324 Ventura Blvd., Studio City, California 91604. In the eastern United States the Dearing Solar Pool Blanket is distributed by the Sealed Air Corpora-tion of Fairlawn, New Jersey 07410. There are also other fine pool covers. Ask a local swimming pool dealer what he recommends. There are also some bizarre and interesting al-ternatives to covers, which have to be taken up and laid back down on a pool. One is plastic air- filled "lily pads" that float on top of the water and hold the heat in. Then there are the many- colored spheres that look like big ping-pong balls. In either case, you order enough of these to cover the whole surface of your pool. Then you can swim, and dive into the water, almost as if they weren't there. These balls seem a little freaky at first, but they're fun, provide pretty good insulation, and are no trouble at all once they're in place. (What's most astonishing about the balls is that once you get out of the pool, and let the water settle down, they will naturally line themselves up in perfectly straight rows and stay that way until the water is disturbed again — re­gardless of the shape of the pool.)

One thing more: Believe it or not, in many cases there is already a beautiful solar collector right next to the swimming pool. We’re talking about the concrete deck. (Your feet know how hot this can get when the sun is strong.) If it were painted a dark color, it could collect an amazing amount of heat from the sun.

Some homeowners have designed portions of their concrete slabs to drain back into the pool itself. In this case, water is pumped out of the pool and through the filter — as it normally is — but then gets sprayed gently and evenly onto the darkened deck surface. From there it flows slowly — and in an even film — back to the pool, pick­ing up heat all the way.

A small architectural engineering firm in Vermont has develop these same lines. They see the whole pool deck as a flat-plate collector — literally. The ‘steel – reinforced concrete slab sits on top of gravel and is insulated against the ground by sheets of styrofoam. The top of the slab is painted black, deep green, or some other dark color that will absorb radiation (Figure 95).

When the slab is warm enough, water is pumped out of the pool and diverted through a series of 1-inch plastic pipes imbedded in the concrete slab about 10 inches apart and 4 inches below the surface. Needless to say, the concrete isn’t as efficient as a copper absorber plate, but it’s more than enough to keep swimming pool water at 82 degrees throughout the season.

Updated: August 21, 2015 — 3:36 pm