Heating the swimming pool with solar collectors: Explanation + tips
More and more pool owners are heating their swimming pools in a sustainable way. The most popular method is heating via thermal solar panels, or solar collectors. But what are actually the benefits of heating your pool with solar collectors?
In this blog, you will learn everything about this efficient and sustainable heating method. We are also looking at three other heating options.
The benefits of a solar collector for your pool
What makes solar collectors such as pool heating so attractive? Here are the main benefits:
> Costs: Solar collectors are fairly easy to install; you usually need not a specialized company to hire. Depending on the system, there are none or hardly any electricity costs. In addition, a solar collector requires low maintenance.
> Flexibility: You can install the collectors on your roof, carport or ground. The vast majority of modules can be installed both horizontally and vertically. Unless you're working with a storage tank, you don't need any other appliances or space for your pool heating.
> Environment: There are hardly any or no electricity costs. Provided you use a reasonable number of collectors in relation to the water volume, you can heat your pool free of charge from +/- May to October. Solar collectors are therefore also very environmentally friendly.
> Subsidy: You may be able to apply for a subsidy for your solar collector and/or storage tank. Check the current terms and conditions in the Netherlands on the website of the RVO.
In Belgium, the VAT is on solar boilers, among others temporarily reduced. The website of Energy Wallonie explains what subsidies are possible in this region. In Flanders, you may also be able to make an additional subsidy get.
The disadvantages of a solar collector for heating your pool
Solar collectors are a relatively simple and reasonably cheap way to heat your bathing water. But there are also a number of disadvantages to this method.
> Autonomy: Assuming you have sufficient capacity in relation to the volume of water, you can heat your pool very cheaply when the sun shines. If the sun doesn't shine, your solar collector doesn't heat your swimming water either (unless you work with a storage tank).
> Speed: Most models automatically recognize when the sun is shining enough to heat the water. If possible, the temperature is therefore “automatically” maintained.
At the same time, the system takes some time to warm up the water. If you only heat your pool with solar collectors, it will take a few days in the spring — depending on the water volume — before the water is really warm.
What is a solar collector?
Solar collectors, or thermal solar panels, are a possibility to heat water in sunlight using the infrared spectrum. Some systems heat the water directly; larger systems work with a storage tank, i.e. in fact with a type of hot water heater.
A solar collector is therefore slightly different from a PV (photo-voltaic)-panel in other words, a “normal” solar panel:
A solar panel (PV panel) converts sunlight into electricity.
A solar collector (thermal solar panel) converts sunlight into heat that heats water for domestic use.
It mileage solar collectors depend on a number of factors regarding the location of installation (e.g. later in this blog) and what you want to use the heat for.
The more sunlight the collectors get, the more heat they can provide. The recommended orientation is between southeast and southwest with an inclination between 20° and 60°.
Solar collectors for swimming pools are most common in the form of mats, too solar mats mentioned. Spherical solar water heaters for swimming pools, sometimes also solar balls mentioned, are based on the same principle.
How many solar collectors do you need for your pool?
How many square metres of solar collectors you need is usually indicated based on the water surface. You cannot calculate an exact percentage here because, for example, you can only work with an average value when it comes to the number of hours of sunshine.
So let's look at an average scenario.
- You have an outdoor pool in North-Western Europe
- You cover your pool when it is not in use
- You use a cover with reasonable thermal insulation
- Your swimming season lasts +/- from May to mid-October
In this typical case, you need an area with solar collectors that at least 55% amount of the swimming surface. With this surface, you can see the water temperature increase by around 5 - 7°C compared to an identical swimming pool without heating.
Example:
You have a swimming area of 8 m x 5 m = 40m2 and you can place your solar collectors towards the south and at a 45° angle.
In this almost perfect situation, you need an area of solar collectors of
at least 55% of 40m2 = 22m2 .
The greater the deviation from the ideal placement (see above), the more you need to increase the percentage to achieve a comparable return.
The biggest factor in heat loss is the size of the water surface. It makes a big difference if you opt for a (small) plunge pool or if you're going for a (large) standard swimming pool. The efficiency of solar collectors depends mainly on the angle of inclination and the toward where the collectors are focused.
Ideally, you should grab your solar collectors south facing aim, in a angle of inclination between 20° and 60°. Collectors oriented to the southeast or southwest with the same degree of inclination also have a reasonable yield.
The more you deviate in terms of inclination and direction, the less efficiently the collectors work.
What are the costs of solar collectors?
Solar collectors for swimming pools are usually placed next to the pool. In this case, the solar mat is simply installed in the water circuit and your normal circulation pump is sufficient.
If you want to place the collectors further away, discuss your options with the provider. For example, you may need an additional pump.
Compared to other heating options, solar collectors are relatively cheap. For a set of 4m2 (including installation material) you pay around 200.00€.
Save on your heating costs
No matter which pool heater you choose, you can reduce your energy consumption by minimizing heat loss. By far the biggest factor in this is heat loss due to evaporation.
That's why it's essential to cover your pool when it's not in use and with you pool cover to ensure good thermal insulation, especially in the colder months.
The bigger it water volume of your pool, the more energy you need to warm up and keep your outdoor pool warm at the start of the swimming season. So go for a small one and with that sustainable swimming pool!
Once the bathing water is (more or less) at the desired temperature, it's mainly about heat loss through evaporation at the water surface. The bigger it surface, the more energy you need to maintain the temperature.
Heat is also lost from the sides and bottom of a swimming pool, so you can also make a profit with insulation, but in comparison, this loss is much smaller.
This article is primarily about heating an outdoor pool. In principle, the same applies to indoor pools, although a little less energy is usually required indoors for pool heating.
Alternatives to solar collectors
Now let's take a look at the alternatives at a glance:
1. Heat pump
A heat pump compresses air and thus creates heat that is released to the water via a heat exchanger. Heat pumps are extremely energy efficient and effective.
You are not dependent on the sun, but please note that some heat pumps lose efficiency at low (outside) temperatures. Note: there can be a lot of difference in the noise that heat pumps produce.
2. Inverter heat pump
A conventional heat pump is always running at full speed; an inverter heat pump runs as fast as necessary to meet demand, so almost never at 100%.
As a result, an inverter model is even more efficient and causes less noise. On the other hand, there is a higher purchase price.
3. Heat exchanger
A heat exchanger transfers heat from one system to another. For example, if you have a modern central heating boiler, large boiler or solar collectors for your tap water, you may also be able to heat your pool with a heat exchanger.
However, your existing heat source must have sufficient capacity. Ask an expert for advice. In the case of a new building, you can include this aspect in the planning.
You always need an expert to install a heat exchanger. Depending on the overall demand, the “source system” sometimes also has to run faster, which increases your energy bill.
Of course, you can also combine two heating sources. Solar collectors for sustainable, free heat and, for example, an inverter heat pump that is energy efficient on slightly grayer days.
Looking for a sustainable swimming pool?
The smaller the water volume, the more economically you can heat a swimming pool. The more compact the water surface, the less water (and therefore heat) evaporates.
Of course, this should not be at the expense of fun and sporting opportunities.
A compact swimming pool is also much easier to heat with solar collectors. You need fewer square feet of collectors to achieve the same effect.
The Swimm Intelligent Pools have a swimming area of 4 m x 2.25 m or 6 m x 3 m, and a water depth between 1.25 m and 1.5 m. Thanks to a state-of-the-art countercurrent system Despite these super-compact dimensions, you can swim just like in open water.
Discover the world of Swimm. Take a look at our website or make an appointment
to try out swimming.
