Individual Solar Water Heater

How to produce hot water using the sun?

The production of solar domestic hot water makes it possible to use free energy from the sun. The operating principle of an individual solar water heater is simple. The technologies, equipment and materials are easy to access and suggest an operating life of more than 20 years.

We have chosen to highlight self-draining technology because its operating principle is the simplest on the market and these installations require little maintenance.

What is a pressurized solar water heater?

The pressurized solar water heater is the most common solar water heating system. In fact, it is a direct result of traditional heating manufacturing techniques with steel tanks, the production cost of which is now under control. In addition, the pressurized solar water heater adapts much more easily to renovation.

A circulator switches on when the tank needs to be heated and if the temperature of the sensors is higher than the temperature of the tank. The balloon then heats up thanks to the energy of the sun. When there is no sun, an electric or hydraulic booster keeps the top of the balloon at a temperature of 60° C on average.

Due to their steel composition and to avoid corrosion, pressurized solar water heaters are permanently charged with a mixture of water and glycol at 3 bars. Glycol is necessary in winter to prevent solar collectors from freezing. A glycol solar installation must be maintained at least every 2 years (replacement of the mixture or readjustment of the circuit pressure).

Why the self-draining system?

1. To eliminate the risk of freezing or overheating.

Regulation, via probes at the sensors or the tank, deactivates the pump if the sensors are too cold or if the tank is at temperature. The heat transfer fluid (water) then flows into the tank and there is no longer any risk of overheating or freezing in the sensors.

2. To do without glycol.

With a classic pressurized solution (non-self-draining), glycol is necessary. It prevents the heat transfer fluid from freezing in the pipes and repels the vaporization of this fluid at the sensors beyond 100° C. However, it does not completely avoid the risk of overheating.

To protect yourself from this, you must be able to install a thermal discharge circuit.

Otherwise, the vaporization at the level of the sensors creates tarring which over time deteriorates the system. In addition, the water + glycol fluid transports heat less well than water alone.

How does the self-draining system work?

The solar collectors are only filled when there is sufficient sunlight and the storage system can still absorb heat. In this case, the pump system of the control module starts up briefly and fills the sensors with storage water. When there is insufficient sunlight or the maximum temperature of the tank is reached, the pump stops, the sensors drain and the installation remains inert.

In addition, the self-draining tank is made of polypropylene, so it is insensitive to corrosion. Indeed, on a self-draining system, the corrosion phenomenon is accentuated, because the water circuit is at atmospheric pressure with the presence of air.

The tank contains accumulated water called dead water. This water stores calories. When there is a withdrawal of domestic hot water, the cold water which enters the tank passes through an exchanger embedded in this dead water, this domestic water heats up and is sent to the withdrawal point. The volume of domestic hot water stored is very weak. Its quality is not degraded as it could be after too long storage in a conventional flask.

Because there is no need for glycol and since the circuit is not under pressure. There is no “heavy” maintenance to be carried out on a self-draining installation.

You can directly come and discover a solar thermal water heater at our Lyon store at our store located in the Lyon region. Different models in stock so you don't have to wait for your merchandise.