Small Scale PV-Power - On Site Use Maximization through Smart Heat Pump Control

Small scale grid-connected photovoltaic (PV) power plants may lead to unwanted disturbance to the electricity grid. In addition, low feed-in tariffs motivate the homeowner and operator of the PV plant to maximize the self-consumption. A PV system in connection with a compression heat pump (HP) for heating (and cooling) purposes of a single family house equipped with some kind of thermal storage poses an interesting optimization problem in this context. Load management is possible through an intermediate thermal storage such as a simple water storage tank. However, in addition the building may comprise a thermally activated building system (TABS) such as a floor heating or an activated ceiling. Thermal storage capacity enables to maximize the utilization of PVpower to pre- or ‘overheat’ the water tank or the whole building, and at the same time the grid is prevented from overcharge and thus regulating (power) requirements are reduced. This research investigates a system consisting of a small grid connected PV plant in connection with a HP charging a thermal storage. The load of the storage comprises domestic hot water draw offs and the space heating demand of a single family house. The main challenge is to maximize the PV-electricity self-consumption. The work presented herein is a preliminary study for a more complex system described in the introduction.