Einfluss der Wärmespeicherfähigkeit auf die energetische Flexibilität von Gebäuden

Influence of thermal mass on the energy flexibility of buildings.

Usually Buildings with photovoltaic systems feed a large amount of electricity into the public grid. Shifting duty cycles of the heat pump into the daytime would therefore be a possible means to greatly increase the self-consumption of a well isolated building. However, thermal comfort should not deteriorate. The impact of the thermal capacity of the construction and the limitations of reducing heat pump run-times on operative temperatures are investigated by transient thermal building simulation. The simulation is validated with monitored data from a small residential building.
The results obtained show that a well insulated building must have a middle or high thermal capacity to be able to limit the run-time of the heat pump to daytime without incurring a non-negligible loss of thermal comfort. The run-time limitation proves to not be possible with a lightweight construction (low thermal capacity). Due to the long daily intervals without heat input, the fluctuation of the operative temperature is higher than with continuous heat pump operation. The level and fluctuation width of the operative temperatures should be in accordance with requirements from comfort standards. Results from the work described herein clearly show that a discussion about requirements in comfort standards versus energy flexibility of buildings must be initiated.