No other energy loss plays a major role in the heat balance of a swimming pool. So eliminating or reducing evaporation is always the first action to take.
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How Long Does It Take For A Solar Pool Cover To Work
With full light, you can anticipate gaining a degree per day, resulting in an 8-degree increase in roughly 6-9 days. In addition, a solar pool cover traps heat in the pool water. When the temperature drops at night, the pool water begins to condense, drawing the heat out of the pool.
How Do The Solar Pool Covers Work?
The logic of these covers is very simple. It is a floating cover that significantly slows the evaporation of water from the pool while reducing heat loss. The rate of evaporation is variable depending on the location of the pool (indoor or outdoor), its geographical location, water temperature, humidity, etc.
The wind is also an element that greatly increases evaporation, so having a sheltered pool (making sure that this shelter does not decrease its exposure to sunlight) is a good rule to follow for energy efficiency.
The use of the covers and their type depends on the type of pool on which we want to intervene. We proceed therefore by distinguishing the two main cases: indoor pools and outdoor pools.
Solar Cover For Outdoor Pools
Outdoor pools are the case where the use of the Solar cover has the most intuitive effects: evaporation issues are maximum and, in case you want to heat the pool with a heat pump, installing a Solar cover beforehand can lead to savings on energy bills of 50% or 70%.
The most suitable type of cover for outdoor pools with good insolation is the bubble cover or otherwise a semi-transparent cover that lets sunlight through. In this way it creates a kind of greenhouse effect: the sunlight can heat the water while the cover limits the dispersion.
Even with this simple device, it is possible to reach considerable temperature increases, even of 8° in ideal conditions.
Functioning of the Solar Bubble Cover.
If the roof were not transparent, it would perform only part of its function, that is, it would be perfect for retaining heat but would not use the energy that the sun gives us for free.
This is why bubble Solar roofing is sometimes also called solar roofing.
Although transparent, these Solar pool covers partially reduce the absorption of heat from the mirror of water. This reduction, to be taken into account, can be counted in the order of 5% or 20%, depending on the material of the cover (more or less transparent).
For smaller above-ground pools there are in fact the so-called solar rings, plastic circles that maximize the effect of attraction and transmission of heat (but they work mainly for small above ground pools, otherwise you should buy an Solar cover). A totally opaque cover would reduce insolation by 40%.
In addition to the savings on heating, a Solar outdoor pool cover reduces evaporation. It also reduces the need for topping up and with it the use of chemicals by up to 40%. Considering that chemicals are one of the most significant items of expenditure in the maintenance of the pool, this is a very important point in favor!
Another trivial but important implication is the protection of the pool from dirt, which in summer is deposited incessantly on the pool water, requiring continuous skimming.
Following the reasoning carried out so far, the Solar covers should be stretched in all periods of non-use of the pool, and then be rolled up automatically or manually (we will explain in another paragraph how to use and manage the covers).
Solar Cover for Indoor Pools.
For indoor pools, such as public pools, the Solar covers a slightly different function. As there is no direct radiation, the cover can be totally opaque, in fact usually used covers with foam structure, thicker than normal bubble covers. The main material is closed-cell polyethylene, adequately treated and protected against the action of UV rays and chemicals present in water.
These covers also have a better thermal insulation coefficient. It allows maximizing energy savings by reducing water evaporation to the minimum possible. They also have a mechanical resistance, and therefore a duration in time, incomparably greater than standard covers.
In an indoor swimming pool, as we have seen, one of the major items of energy loss is ventilation. The Solar cover, if used correctly, decreases the need for ventilation.
A secondary effect of less evaporation, in fact, is the reduction of annoying chemical components in the air (just think of the pregnant and ubiquitous smell of chlorine that you breathe in public pools) and consequently reduces the need for ventilation.
The other characteristics are very similar to those already exposed to outdoor pools.
Advantages of Solar Roofing at A Glance
- Significant reduction in evaporation
- Greenhouse effect for outdoor pools with transparent covers
- Reduction of debris deposits on the water surface
- Reduced cleaning time
- Reduced topping up
- Improved air quality in indoor pools
- Reduced chemical usage
- Save money on water heating bills
- Increased water temperature, i.e. reduced heat loss
How to Use a Solar Cover
The use of the Solar cover should be fairly clear after the previous explanations. It should obviously be withdrawn during the hours when the pool is in use and spread out when the pool is not in use (mainly in the evening for public pools).
In general, the Solar cover should not be abandoned in the sun, especially on the hottest summer days: during peak hours it is better to keep it wrapped to its roller, protected with a reflective sheet. Better to use it in the intermediate hours and in the evening, to prevent evaporation.
This is to avoid a too rapid consumption of the sheet. Also to prevent the pool water from becoming a real broth, difficult to manage at a chemical level.
This work of shrinking and stretching is too costly to be done manually. For this reason, unless you have a very small pool, it is always advisable and often necessary to purchase, along with the Solar sheet, a roller winder.
A roller is nothing more than a shaft made of aluminum, plastic, or steel that is placed on one side of the pool. It has a crank handle or motorized system that can completely retract the cover, wrapping it around.
The rollers can be quite complicated mechanisms when it comes to covers for public pools or pools with very particular forms.
Hence it is advisable to get a quote before buying these accessories so that someone in the trade can advise you on the best product.
For example, if you have a pool with salt disinfection you will need to buy a roller with components in AISI 316 steel, which resists salt corrosion.
As for the characteristics of the cover just keep in mind the following rules:
- The cover must rest on the surface of the water.
- Its size and shape must correspond to that of the water surface.
- When the sunshine is very strong, it is advisable to roll up the cover and protect it, both to make the best use of solar energy and to preserve the life of the cover itself, avoiding the stress of strong sunshine and high temperatures.
- The cover must be removed during shock chlorination operations to avoid damaging the material.
- When the cover is rolled up, it is advisable to protect it with a reflective sheet.
Now you know everything you need to know about Solar covers and you are ready to make the most of your pool!
