Is there a risk of clogging with DualSun Spring panels over time due to the air permeability of the heat exchanger?

No.

Clogging occurs by metallic corrosion. Since the exchanger and the DualSun links are made of polymer, they will not be affected, but other elements of the circuit could be.

Nonetheless we recommend to:

• make sure to degas the system correctly during commissioning,
• use systematically demineralised water and an anti-corrosion glycol (TYFOCOR) during filling of the closed circuit.

The very low air permeability of the DualSun heat exchangers and hydraulic links allows air to escape from the solar circuit, however air cannot enter the solar circuit.

The DualSun exchangers, made of polypropylene, work mechanically under the effect of internal pressure, and over time it can be seen that the pressure in the solar circuit slowly drops until it stabilises at the system's head pressure.

The pressure in the exchangers is balanced with the atmospheric pressure surrounding the DualSun panels.

The heat exchangers thus behave like free membranes, therefore ensuring a constant equilibrium between the internal pressure and the atmospheric pressure.

On the other hand, the heat exchangers and hydraulic links shrink, just like the heat transfer fluid, in cold temperatures. No negative pressure in the solar circuit was found in this case.