The forced circulation solar systems are designed and developed for both installations where there is big demand in hot water (complexes, hospitals, sport facilities, hotels etc) and domestic use, in case the water storage tank cannot be placed above the collector due to static or aesthetics reasons.
The said systems consists of the solar collectors, the water storage tank, the heat pump and the necessary automations, which ensure the circulation of the fluid included in the collectors. Thus the relative position of the tank and the collector(s) is not affecting the operation of the system. The auxiliary energy in order for the needs in hot water to be covered in bad weather conditions is conveyed to the tank or to the water outlet.
The auxiliary energy derives from a hot water boiler, but in many cases, there is also the possibility of use of a heating element.
These systems are closed circuit systems. A heat exchanger comes between the collectors and the storage tank, thus preventing the water solution from being mixed with the storage tank water. The heat exchanger could be placed in the tank (internal) or outside (external).
The automations of the system constantly check the temperature difference between the solar collectors and the storage water tank and send orders accordingly, in a way that the constant hot water generation is ensured, always according to the system settings.
The differential thermostat is electronically programmed to control the differential temperature and is equipped with buttons and a screen, in which parameters and messages are displayed.
They are also equipped with:
• Anti- frost protection for the closed loop
• Overheating protection of the closed loop
When the solar collectors temperature is higher that this of the tank by 6-10°C, the circulation pump of the system is activated (differential ignition temperature). The circulation pump will stop working when the temperature difference is 2°C (hysteresis).
In case of non-adequate solar radiation, there is the possibility of function of the auxiliary energy source.
The forced circulation solar systems are available in specific sizes and cover specific needs in domestic hot water, but they can also be custom made.