Optimal design of PV and HP system

Methods of utilizing residential produced photovoltaic (PV) power by converting to thermal energy through heat pumps (HP) are present in literature, where thermal energy is dispersed as either heat or hot water at the instant moment of PV production. In this paper an alternative solution is described, where the thermal energy is stored in a buffer tank (BT) capable of dispersing heat to either the heating system of a house or a hot water tank, for later use.

The thermal storage solution including a BT can increase the self-consumption of residentially produced PV power and thereby shift electric energy demand of the HP to hours where excess PV power is present. The self-consumption of the PV energy affects the overall net present value (NPV). In this paper, a method which maximizes the NPV by finding the cost-optimal combination of PV, HP and BT sizes, is proposed.

Results show that the thermal storage with a BT is a better investment than a PV system without HP or no investment. Furthermore, it showed that the optimization model developed in this project is capable of finding the optimal combination of component sizes based on our data.