Numerical study on load shifting strategies for the heating and cooling of an office building considering variable grid conditions

In this simulation study, the load shifting potential of a plus-energy office building with local PV generation, a ground-coupled heat pump and TABS using the heating and cooling system is discussed. The evaluated load shifting strategy uses the building mass as a thermal storage by rescheduling the delivery of thermal energy to the zones, based on the availability of local PV generation and the fraction of wind and PV in the public grid. It is implemented as a co-simulation of Dymola (for simulation of the full system) and Python (for the load shifting algorithm and test of comfort criteria using a functional mock-up unit (FMU) of the building). Using the presented strategy, self-consumption and autonomy of the locally produced electricity can be increased by 3%abs and the grid support coefficient GSCrel of the heat pump can be increased from -11 to +58 while maintaining thermal comfort. Between spring and autumn, the load shifting potential of the heat pump is limited due to low heating and cooling demand. It can be increased by a factor of 2-3 if the comfort requirements are relayed by a soft constraint. Load shifting decreases the efficiency of the heating and cooling system by 2.8%.