Electricity demand flexibility performance of a sorption-assisted water storage on building heating

The energy performance and energy flexibility potential of a sorption-assisted water storage (SAWS) for a medium-scale residential building with eight apartments under the climatic condition of Potsdam, Germany were investigated. The SAWS system consists of a stratified water storage coupled to an adsorption heat pump (AHP). The driving heat source for the AHP was modeled as an ideal heater, which can be interpreted as an electric heater to serve as an off-peak storage heating system. Five representative partial heating loads of a building were investigated. Recharging situations of 2 h, 4 h, and 8 h with an interval of 2 h heater switching off were considered. Transient simulation results show that the 2 h heater switch off is feasible and does not significantly reduce the occupants thermal comfort in the four low heating load cases. However, for the highest heating load case, the load cannot be completely met. An average heating coefficient of performance of 1.33 for all the five load cases is achieved. Additionally, under the simple control scheme considered here, this SAWS system achieves high electricity flexibility by controlling the heater switch on and off schedule for a demand response program.