SYSTEMS

· forced circulation · natural circulation · once trough · solar plants ·

This hook-up is suitable for small plants, in particular for the «do-it-yourself». It has the advantage of not requiring neither circulation pump nor regulation devices nor electric feeding.

To provide a satisfactory efficiency, the panels must be installed with a slope of almost 30°, otherwise the natural circulating water could be unable to remove possible air bubbles and, hence, to circulate along all the panels.
The solar plant is fed from the mains through a Vrp pressure reducer valve, set at 3 bars.

When the panels are hotter than the Sr accumulation tank, a circulation start naturally. This that drives the hot water into the Sr accumulation tank while, from its bottom, colder water goes down into the panels. The water flows trough the panels in parallel; possible air is discharged in the Sr accumulation tank. The more the Sr accumulation tank is higher than the Bs solar panels battery, the more active the natural circulation is.

As in whichever solar plant, it is better that the Sr accumulation tank have no thermal backup why this last interferes with the solar plant operation reducing the efficency of relevant amounts.
Down-stream the Sr accumulation tank, the Mt thermostatic mixer increases the water temperature, when too low, mixing it with very hot water prepared in a Scb auxiliary heater.

At the end of the operative season, a protection against the frost must be provided; if the panels have been installed with a sufficient slope (almost 20°), it is possible to drain them, otherwise they must be filled with a brine of water and sodium chloride that prevent the freezing down to -20°C.