22 September 2011
The knowledge about the reduction of heat demand in dwellings has reached a
sophisticated level, especially regarding the building envelope. The next step are net zero energy buildings, where the total amount of yearly energy demand is covered by building
integrated generation of energy from renewable sources. The most promising technologies are solar heat panels, photovoltaics and heat pumps. But it is not yet obvious which combination is best.
In a simulation study two combinations of air-to-water heat pumps with either solar thermal collectors or photovoltaics have been scrutinized. All system components applied are field proven and available on the market. The results show that both combinations are nearly equivalent regarding energetic efficiency, economical feasibility and environmental impact. Although the heat pump was sized to cover space heating and domestic hot water demand, the focus lays on the domestic hot water preparation. Both systems cover 50 % of the final energy demand for domestic hot water from solar irradiation, required by local regulations.