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Solar Pool Bubble Blankets - Will They Warm My Pool

Posted by Dr Gregory Grochola (physicist) on 31st Jan 2019

So we get asked do solar pool covers really work, do they really heat the pool? Well it depends.

We thought it might be interesting to analyze pool temperature boosts from transparent (bubble type) solar pool blankets using our new heat loading simulator (validated against the heat loading standards AS 3634-1989 and ISO TR 12596 1995 here). So what we did was calculate the blanket temperature boosts under various pool heat loading conditions, during shoulder pool heating months for all Australian capitals.

Transparent Pool Blanket Pool Water Temperature Boosts

A word of caution here: all the below calculations are for blue, bubble style transparent blankets. Darker blankets will not be as good in terms of energy conservation as they block the sun and cool the pool (Czarnecki, CSIRO TR19, 1978).

In the table: "Shade" means shading on a pool. "Windy/Exposed" or "Sheltered" specifies the pool is either fully exposed to a windy area or fully sheltered and situated in a wind-sheltered area respectively (two extremes). "Light/DarkWalls" refers to the colour of the pool floor and walls. Lastly, solar means the inclusion of a solar pool heating system (67% OKU panel coverage).

State Capital
50% shaded
Windy/Exposed
Light Walls
No Solar
0% shaded
Windy/Exposed
Light Walls 
No Solar
0% shaded
Wind/Sheltered
Light Walls 
No Solar
0% shaded
Wind/Sheltered
Dark Walls 
No Solar
0% shaded
Wind/Sheltered
Dark Walls
Solar Heating
Hobart
2.7
4.1
5.1
5.3
9.1
Melbourne
3.1
4.7
5.6
5.8
9.8
Canberra
3.0
4.8
5.9
6.1
10.2
Sydney
3.1
4.6
5.4
5.6
9.3
Perth
3.0
4.5
5.5
5.7
9.6
Adelaide
3.7
5.4
6.3
6.5
10.3
Brisbane
2.3
3.9
4.8
5.0
8.9
Darwin
3.3
4.9
5.7
5.9
10.0
Temperature boost from a solar bubble cover on 100% of the time

The table shows various temperature boosts from the use of a solar bubble cover on 100% of the time in the heating months when used for that specific situation. Note: these are averages, over day and night, warm spells and cold spells. Secondly, note for situations involving the use of a solar pool heater, these boost temperatures are NOT the TOTAL pool temperature boost from solar heating + cover - they are just the temperature boost from the pool cover ALONE when added to a solar heated pool, as here we are just analyze the effects from adding a pool cover. For temperature boosts that result from adding a solar pool heating system see this analysis.

Regarding the present results what's immediately clear is: the more solar energy going into the pool the greater the temperature boost an insulating pool cover is going to have. And this makes sense from a physical perspective; a solar blanket doesn't introduce heat, it only insulates whatever heat input you have. So if you don't have the heat input on one side of the heat/loss equation, then a solar blanket won't do that much.

The last column is the temperature boost you get from the addition of a pool cover ALONE to a solar heated swimming pool. You get a whopping 9-10ºC temperature boost by using the cover under this situation. So the lesson here is if you've got a solar pool heater and you're not using have a pool cover you're missing out on 9-10ºC during the shoulder months! There is a non-linear, synergistic effect when using both a pool cover with solar, this article describes this effect and why it comes about.

Perhaps this is an obvious finding now but - heating AND insulation go hand in hand for the best results.

Do you want to know how well a pool blanket will work for a specific set of conditions? Head over to our simulator and have a play with it :)

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