Dynamic simulation of a heat pump for building applications oriented to assess the potential for demand response and ancillary services supply

The building sector and the policies aimed at decarbonising its energy uses are expected to play a crucial role to achieve the climate targets. Attention has been arising on the capability of this sector to provide flexibility to the power grid through the implementation of Demand Response programmes via reversible heat pumps. In the present paper a detailed analysis of the flexibility induced on the electric load by different demand response programmes is presented, assuming a large standard office building as a case study. After developing an integrated TRNSYS model including the building, the hydronic network, the heat pump and a thermally stratified water tank, dynamic simulations were performed for three different demand response strategies, all aimed at shifting energy consumption from peak (high energy price) hours to off-peak (low-price) hours, but each one implying peculiar setting in terms of time schedules and temperature setpoints. The results show that the resulting electric load profiles are highly sensitive to the flexible operation strategy adopted, the three scenarios achieving different peak-shaving results and energy savings (due to more efficient operation of the reversible heat pump) ranging between 11.93 and 21.55%. The effects of thermal inertia both with regard to the building and the water tank is also discussed, as well as the impact on thermal comfort of occupants that could be induced.