Heating a swimming pool with plastic solar panels can be an easy and inexpensive operation, which you can also do yourself in a few steps. Keep in mind, though, that plastic solar panels have a lower yield than more expensive and highly efficient solar panels made of steel, aluminum, glass or copper. Certainly the low cost of the system in relation to its effectiveness and the practicality of installation are elements that play in favor of plastic solar panels.
Steps
Step 1. Before you begin, consider the climate and try to balance your expectations
The night temperatures, in fact, tend to cancel the heat collected during the day, even during the summer season. It will therefore be necessary to cover the pool during the night, when the outside temperature drops and the heat dissipates more easily. An inground pool will disperse heat more easily than an above ground pool as, in many areas, the ground below 3 meters above the surface is very cold, even in the summer months. Also, see if you have enough space to install the panels so that they are exposed to direct sunlight all day, decide whether to remove the panels during the winter months or during severe thunderstorms, try to figure out if the water flow reduced is sufficient to keep the pool clean or it is necessary to make the pump work more. After all these considerations, the low cost of some panels and the practicality of their installation will make your experiment feasible. As a rule, plastic solar panels work very well during the summer months, but they will not be able to heat the pool even in the slightly colder months without the help of an additional gas heating system. Experiment and find the solution that's right for you.
Step 2. Install a three-way valve after the pump and filter (in the return line) so that the water is directed to the panels or to the pool (avoiding the panels)
Normally, pool valves are quite expensive but will serve to not block the return flow of water and can be adjusted to let all or part of the water flow through the solar panels. Buying a valve with an automatic control system will allow you to adjust the valve remotely or activate it in certain time windows you select.
Step 3. Install a T-tube near the 3-way valve in the same return line, at the side of the pool
The water returning from the panels will re-enter the return line under the valve; it will then be able to pass from the panels to the pool. For the winter months it is also very useful to purchase valves that have joints so that the system can be fully opened and drained.
Step 4. Choose a pipe that is the same size as the return pipe (usually 3, 8 or 5cm) for the lines going to and from the panels
If the panels will be installed on the roof, you will also need to install plastic hooks to hold the pipes and secure them well to the walls and the eaves. On the edge of the roof, install a fitting union on each pipe to remove the panels more easily at the end of the summer season, in the event of severe storms or for roof repair; the same goes for solar panels installed on the ground. You should also bury the pipes in the pool, so as not to spoil the aesthetics of your garden.
Step 5. Plastic solar panels come in different sizes, but the most common measure 2-3 square meters
Buy at least two, trying to keep an eye on the price; you could take two at the beginning and consider buying more in the future. If you have enough space and want to heat the water well, you should buy enough panels to cover the entire area of your pool. For example, a round pool with a diameter of 5.5 meters has an area of about 17 square meters, so you will need at least 5 panels to heat your pool well. You can use even fewer panels to keep the price of your investment low. Also, consider that if you use a number of panels you will also need a feed pump, so consider what to do after purchasing the first two test panels. Usually, it is necessary to increase the size of the pump by 1/4 hp to get more abundant water flows.
Step 6. Fixing the roof panels could be the most difficult operation, which could make you lean towards a ground installation
Use stainless steel screws that you can also find on the internet if your city hardware does not have them. Measure the space between the roof beams and insert the screws at a distance that is slightly wider than the size of the panels. A generous "spread" of polymer bitumen on the screws is ideal for fixing everything well. Insert an aluminum bar with holes at the ends above the panel and fasten it with screws. Secure everything with stainless steel washers and wing nuts to make removal easier and faster. In some countries it is necessary to send the drawings to the Municipality, to respect some regulations and to obtain a permit before installing objects on the roof. These elements could make ground installation a more attractive solution.
Step 7. Once the panels are attached, connect them to each other and attach them with fittings
Pay particular attention to which panel tubes the outgoing and inlet flows correspond to. Remember that the water flow must enter one side and exit the other and if the pipes are installed in reverse, air will remain trapped in the panels. Also, remember that if the panels have been mounted on a slope, the water outlet should be higher than the inlet.
Step 8. Once the hoses are connected, turn on the pump and open the valve to let the water flow to the panels
Check for leaks. In theory, the larger the water flow, the more efficient the system will be (because a certain amount of cold water in the panels absorbs the sun's heat more). You will notice that initially the water will be only two or three degrees warmer, but after a full day the panels will be able to significantly increase the temperature. Even for a small pool, it will take a few days for it to warm up well. If, on the other hand, the outside temperature remains high during the night, you will notice that the water in the pool will heat up a few degrees every day.
Step 9. If you live in an area where the temperature drops below freezing, be sure to install a drain at the lowest point of the system or remember to pressurize the pipes with air to avoid damage during the winter months
Step 10. An automatic control system can be purchased for around 500 euros and includes temperature probes, valves and actuators to automate the system
Advice
- Many pools take six hours to complete the cleaning cycle. Solar panels usually increase this time by taking advantage of solar hours. A hot-water pool will require more cleaning than a cold-water one.
- If the panels are in danger of freezing, they will need to be drained. An additional tube to let the air in from above could make this easier.
- Do not circulate the water through the panels if the sky is dark or there is no sun. The panels could also make the water cold in the evening and at night.
- Automatic regulators are used to regulate the water temperature and to open or close the valves that make the water flow through the panels, as needed. Automatic regulators may also have a clock to control the pool pump, but they cost around $ 500 and require a power transformer and temperature sensor.
Warnings
- Do not put chlorine in the channels that pass through the panel.
- Although polymer solar panels are light when empty, they can weigh a lot when filled with water. Do not install them in the roof without fixing them, as the wind may cause them to fall.
- Do not try these operations if you have no practice or if you have no idea how to do them safely. Instead, ask a professional for help.
- Many administrations do not authorize the installation of roof panels without a specific plan or authorization. There are also local regulations that determine what you can install on your roof and how.
