Solar station for managing a drainback solar system also called solar drainback
Technical presentation of the PAW DrainBloc solar power plant for solar drain systems.
Why a solar system to empty?
During good irradiation, the sensors quickly heat the storage tank. But when heat is not required, for example during holidays, the collectors cannot transmit heat to the already hot storage tank.
The installation overheats and the solar fluid vaporizes. The pressure forces the hot solar fluid into the tubing. This condition is called stagnation and although it is not a serious incident, high temperatures and pressures are critical and undesirable.
The solar fluid vaporizing in the sensors can suffer.
In conventional solar systems the steam is even pushed into the solar station and the expansion vessel. Seals and diaphragms are adversely affected by heat which accelerates component aging and reduces the longevity of the installation.
The DrainBloC offers a brilliant solution: the self-draining collector field. As the installation is not completely filled with the heat transfer fluid, the sensor empties automatically as soon as the circulator is switched off. The heat transfer fluid is collected in the integrated reservoir of the DrainBloC. As there is no more heat transfer fluid in the hot collector field, steam and pressure do not form. In this system stagnation is simply not possible, so an expansion tank is not necessary.
As soon as the circulator is put back into operation, the sensor field is filled with the heat transfer fluid of the tank and the heat can be transported to the storage tank.
Main advantages of a solar drain system:
- no stagnation
- no risk of freezing
- heat transfer fluid totally compatible with the environment [water]
- improved heat transport
- improved heat transfer
- optimum heat storage capacity
More: drain solar panels, why it's better than a pressurized system.