Hybrid heat pump scenarios as a transition towards more flexible buildings

The potential of heat pumps (HP) to contribute to a cost-efficient and environmentally-friendly operation of the electric power system is widely acknowledged. Nevertheless, a large-scale implementation of heat pumps in Belgium is lacking today, with applications restricted to new or deeply retrofitted houses. This paper investigates the potential of a more accessible transition scenario, where heat pumps are used to assist, rather than replace, the original heating system in place. The reference heating system considered is a gas boiler (GB) connected to radiators (RAD). To analyse the behaviour of the hybrid system, a model predictive control (MPC) approach is used. Main interests are the achievable heat pump utilisation, as well as the detailed behaviour of the system. Also the impact of the introduction of the heat pump on primary energy use and operational cost for space heating (SH) is illustrated. To ensure a profound analysis, different scenarios are investigated, where the dwelling characteristics, heating system, objective function and energy prices are varied. The results illustrate that under current price conditions in Belgium, minimisation of the primary energy use is the only beneficial scenario leading to a considerable heat pump utilisation. When minimising operational costs, a lower electricity-to-gas price ratio (EGR) is needed to tip the balance.status: publishe