PVT as a direct source for the heat pump
PVT collectors are also used as a direct source for S/W heat pumps, without seasonal heat storage.
This is a good alternative to L/W heat pumps, but not as efficient as a (regenerated) geothermal probe or ice storage solution.
For this application, we recommend a cold storage tank (hydraulic separator between the PVT and source side of the heat pump) and a heat pump that is approx. 20% oversized and a hot water storage tank that is approx. 50% oversized. This allows the operating times of the heat pump to be shifted to the day as far as possible. We also recommend forced charging of the hot water storage tank at 1.00 pm to 5.00 pm.
However, in order to ensure the operational reliability of a system even in the worst-case scenario (over 24 h cold and grey), an additional heat source for peak load coverage is expedient, which keeps the cold storage tank at least at the permissible source temperature of the S/W heat pump during full load operation of the heat pump on these few days of the year.
As an approximation, 20 hybrid collectors (40m2) and an additional heat source with 4 kW heat output are required per 10 kW of heat output for peak load coverage at -7° and overcast skies.
With our PVT Solar - condensation ice storage tank +++ instead of a conventional cold storage tank, you not only increase the storage capacity, but also gain an additional heat source. This increases the efficiency of the system and makes the use of an electric immersion heater superfluous, even when the collectors are covered in snow.
