Pool covers (solar)

[bssage]

It seems to me, that there is a fair amount of really useless information about "Solar Covers" on the internet. As the saying goes opinions are like ___holes (everyone has one).

It also seems to me, that if a person had the means. It would be fairly simple to reach a real answer to the question's, Black, Clear,, Blue,,,thickness effect on water temp ect. . .

Surely someone on the forum owns a pool supply store, or has a buddy that does and could do some fairly simple experiments with material swatches to see conclusively which color's or thickness add value to the purchase?

My opinion (ha) would be that the transparent/black would allow light and absorb heat. But honestly, it's just a guess.

Anybody want to step up to the plate on this question?

[JimK]

...As the saying goes opinions are like ___holes (everyone has one)....

Lol! Yes, and they all stink! Lol!

My guess would be that a clear cover would work best. It seems black would just be effective in heating the cover itself, while clear would allow the water to absorb more heat. Of course part of a solar cover's effectiveness comes from preventing evaporation which robs the water of heat; any color cover will do that.

Just my guess.

[bssage]

Well until someone will test the theories. I guess we can discuss them. I agree the clear/black will be most effective heating the black plastic. But I also suspect the radiant heat coming from the black would be a more significant source of heat than clear. I agree that using the term "Solar Cover" is a little misleading, as the greatest benefit would come from restricting evaporation.

Back to the point of the OP. All of this really does not need to be subjective. If I had different samples all I would need is dishes of measured water and a digital thermometer. Then scale the results to a pool sized equivalent, or a factor to be used per gal, and everyone would a useful answer. It might even create a completely different answer.

[FormerBromineUser]

Go for it! My own experience with auto-covers seems to be that darker is better for heat generation. Auto-covers don't let the light pass through so not good for comparison there.

However, I went from a light color to dark (same thickness) and subjectively, there seemed to be a greater heat increase with the dark.

[kelemvor]

Solar pool covers have been studied by the US Department of Energy and are considered to be the best way to heat your pool. They don't work as much by getting hot and heating the water as they do by preventing evaporative heat loss over a large surface area. Here's a good read on the subject: http://energy.gov/energysaver/articl...ng-pool-covers

They do indicate that a completely transparent cover will work best in that article.

My personal experience is only with a blue one. It was a big pain in the butt and I stopped using a cover after one season.

[bssage]

and my last one was a PITA. I am thinking about slicing my next one in four pieces. Make it a one person job putting it in and taking it out. It may not be "As" efficient as one piece. But I figure I would be more likely to use it more often if it was less of a job. I'm reading your research link now. Thanks

[FormerBromineUser]

I think WaterMom does that with her solar cover. Look in her posts too.

[chem geek]

Technically, the greatest heat gain comes from a clear insulating cover because most of the sunlight is then absorbed by the water but the heat is largely retained due to preventing evaporation by the cover and with an insulating cover by preventing conduction/convection (though not radiation) of heat. As I note in the thread Water Absorption and Heating from Sunlight, around 60% of sunlight is absorbed in a white plaster pool (a dark bottom pool absorbs even more).

An opaque cover will prevent sunlight from entering the pool to heat it directly. The color of the cover then becomes important where a white or reflective cover will heat the water the least while a dark black cover (especially one that absorbs infrared as well as visible light) will heat the most, but the heat transfer to the pool water will be limited due to convection and radiation and the uneven heating of the pool water. The best result with a black cover occurs if the water is circulated under the cover to keep it cool (same principle as with solar water heating panels) and if the black is on the underside of an otherwise clear plastic cover.

I have a mostly opaque electric safety cover and when it was tan in color it did not have any significant heating but now that it is darker blue it heats the pool a little bit. No where near what a clear insulating solar cover would do, but the difference between a lighter and darker cover is still noticeable.

Most heat loss from pools comes from evaporation. The next largest loss comes from radiation (for outdoor pools, not indoor) and the lowest loss comes from convection though if there is wind then convection losses can be greater than radiation losses, but losses from evaporation are still the largest by far. So any water vapor barrier cover will cut down most of the heat loss by eliminating evaporation. An insulating cover then additionally reduces losses from convection. A completely opaque and well insulated cover will retain the most heat, but it will also block sunlight from heating the pool directly. So indoors that would be best. Outdoors, a clear insulating cover is better as it will let sunlight add heat to the pool.

See this document for the technical methodology used by the EPA for Energy Star® performance ratings for swimming pools.

[JimK]

So my instincts were right.

[bssage]

Nice,,,,Thanks,,

So I am dumbing this down for myself and checking my understanding with your.

Since my pool is an outdoor, AG, In Iowa. I want to both gather as much heat as I can, and keep it in the pool best that I can.

The best "Bang For My Buck" is a clear insulating cover, Not a Solar Cover? Preferably one with a Mill thickness that would allow me to run my pump with the cover on during the hottest parts of the day??

Does anyone have an Insulating cover they recommend??

And hey, If my understanding is incorrect. Feel free to correct me.