Liquid Solar Cover Technology

Welcome back students of pool!

Liquid Solar Covers reduce evaporation with a molecular mono layer on the water surface.

Just pour the clear liquid into the pool and it forms an invisible layer on the surface, blocking heat loss.

Better living through chemistry!

What is Liquid Solar Cover?

This may surprise you, but isopropyl alcohol or a similar fatty alcohol or carbinol is the main ingredient in most liquid solar blankets.

liquid-solar-blanket-molecules

This long chain hydrocarbon has a curious reaction in water. One end is hydrophilic (attracted to water) and other end is hydrophobic (repelled by water). This causes the molecules to stand up straight at the surface, coalesce into a thin surface barrier.

But you can’t just pour rubbing alcohol into the pool! A carrier like calcium oxide or propanediol is used to act as a dispersant, to help the molecules arrange themselves in a single layer, while preserving their natural attraction.

How Effective is Liquid Solar Cover?

Using chemical films to control evaporation is not new, studies on mono-layer chemical films date back to early 1900’s.

For evaporation control, overall study results are mixed, up to 43% across 30 studies, with an average of 20% reduction in evaporation. Differences in product formula, water and air temperature, humidity and wind speed account for differences.

A recent study from 2016 at Cal Poly by NPC found that during a 65 day study, liquid evaporation suppressants reduced evaporative loss by roughly 15%.

How about Heat Loss? Most pool heat loss occurs from the pool surface. Studies have not evaluated heat loss or heat gains, but since surface heat loss occurs as evaporation, one can expect a 15-20% reduction in heat loss, and/or evaporation. This translates to a real heat gain of 3-6 degrees.

What Affects Liquid Solar Blanket Effectiveness?

During high winds, the mono-layer on the surface will shift and as much as half of the surface area may be ‘uncovered’, as the molecules stack-up on the opposite side of the pool.

Humidity and temperature levels, and to some extent barometric pressure can have an effect on actual effectiveness.

Finally, liquid pool covers dissipate slowly and some will be lost to backwashing, splash out or drag off water. A weekly dose of 4 oz is sufficient for most pools.


liquid-solar-blanketsNot nearly as good as traditional solar blankets in stopping evaporation and heat loss, which can be over 80% effective, but much more convenient and easier to use, for about the same cost. I’d say that liquid solar covers are here to stay.