Everything you need to know about solar thermal panels
Thermal solar panels allow you to produce domestic hot water and heating thanks to solar energy. By using renewable energy, you can save up a lot of money on your bills!
How does a solar thermal panel work?
Thermal solar panels can be used to produce domestic hot water and energy for heating. They should not be confused with photovoltaic solar panels (often called solar PV), which are used to produce electricity only.
A solar thermal panel is a surface that captures the sun’s rays to heat a heat transfer fluid placed under the panels. This hot fluid then goes into a storage tank where it heats the hot water used in your house (taps, sinks, showers, etc). In the case of a combined solar system, the storage tank can be connected to two hot water circuits, one for domestic hot water and the second for heating, supplying air conditionning units or underfloor heating for example.
Which savings can be made with thermal panels?
Installing thermal solar panels in your home can save you up to 50% on your energy bills. How can you do this? By using renewable, free and unlimited energy!
To take full advantage of this, your roof must be well exposed to the sun.
What are the different collectors?
Thermal solar panels are thermal collectors. There are several types available:
- Monobloc collectors: these units have a storage tank placed directly on the roof and are often called roof mounted units. They are probably the most popular model in Perth and WA. The advantage is the proximity between the water tank and the panel. On the other hand, the storage tank is more prone to heat loss on the roof as it is in contact with the outside air. In hot areas like Western Australia, this allows the tank to heat by being in direct contact with the sun rays.
- Flat-plate glazed collectors: these are the most common in the residential sector. They consist of a black metal plate that absorbs the solar radiation and is in contact with the tubes containing the heat transfer fluid. High-temperature resistant insulation is placed underneath to trap the heat inside the tubes. A tempered glass pane covers the tubes to protect them and creates a greenhouse effect to further heat the heat transfer fluid;
- Evacuated tube collectors: these consist of several glass tubes placed side by side, in which a black metal plate absorbs the solar energy. These tubes are properly sealed to limit heat loss. This type of collector is really interesting for more extreme conditions.
- Unglazed flat plate collectors: these can be used for heating swimming pools. Less expensive, they are also less efficient and more prone to damage as they are not protected by glass;
To prevent the heat transfer fluid in the pipes from freezing in cold areas, there are anti-freeze fluids available such as glycol water or self-draining systems. On the other hand, if the temperature is too high, draining prevents the fluid from overheating and damaging the equipment.
What is the efficiency of a solar thermal panel?
The average efficiency of a solar thermal panel is between 30 and 40% in general.
What is the efficiency of a solar panel? It is the amount of energy produced in relation to the amount of energy input to the system. The higher the yield of a solar installation, the more profitable it is!
This number is of course different depending on the model used.
What is the surface area of solar thermal panels required for a house?
The surface area of thermal panels required for a house varies according to several criteria:
- the surface area of your house ;
- your needs: production of domestic hot water only, heating only or both;
- the amount of sunlight in your region
- the orientation and slope of your roof.
As a general rule, you should allow between 1 m² and 1.5 m² per household member.
To find out the exact surface area of solar panels required for your home, we advise you to rely on the recommendations of your local hot water specialist. This expert will suggest the ideal size for your solar hot water installation.
