As result, a sharp decrease in the energy demand can be reached if the storage is equipped with two heat zones instead of one.
This can be explained by the decreased set temperature in the additional heat zone for space heating leading to a higher
performance of the heat pump. Other measures with a positive effect on the energy demand are a large space heating volume, the
number and place of sensors, low set temperatures and the sensor position in the upper part of the heating zone.
The investigation gives important recommendations how to connect a heat pump with a storage tank and may be considered as
design rules for all heating systems consisting of heat pump and different types of storage tanks