Parametric Sizing of a Residential Hybrid Heat Pump Retrofit considering Flexibility

Hybrid heat pumps are an intended pathway towards decarbonization of the Dutch built environment. Next to carbon abatement, such systems can provide value as flexibility sources. To the best of the authors knowledge, there exists no methodology to size the heat pump and thermal energy storage of a hybrid heat pump system including energy flexibility. Scenarios were generated based on a Dutch case of four houses, two heating seasons and 42 heat pump and tank combinations. Per scenario, baseline operation was compared to various DR scenarios to quantify downward flexibility potential. The operation was modeled as a rolling time horizon of 8 hours, minimizing energy costs to schedule the heating devices. The results show that heat pumps oversizing increases downward potential, as well as the cost of the obtained flexibility. A trade-off exists in increasing water tank size to improve flexibility but increase losses. Furthermore, the results indicate that the building parameters play a large role in cost and quantity of flexibility, suggesting further research into a fleet of hybrid heat pumps may be interesting.