The Swiss PV wall system to maximise self-consumption in a single building element

With decreasing subsidies for PV energy fed into the grid other economic incentives are needed to sustain the growth of PV power. An effective solution is to increase self-consumption for grid-connected, residential PV systems by means of generating hot water by the use of a heat pump. This widely used concept of thermal energy storage has been adapted for a facade element with integrated PV modules for the first time. The so called Swiss PV Wall System (SPWS) contains all elements needed in the façade, behind the PV modules with a power of 1 kWp, like a PV inverter, a heat pump and a hot water tank. Simulation showed that virtually 100% of the PV energy can be used either by the heat pump to produce hot-water or the household’s electricity needs. A functional model of the SPWS was realized and first measurements showed that the heat demand of a one family household may be covered for the majority of the months during the year. Economic analyses showed that the cost per kWh heat is at about 0.215 CHF and thus lower than standard solar thermal and some fossil solutions