Abstract
Building clusters and district heating systems have large thermal inertia, which can serve as thermal storage units and regard as important flexible resource. In this study, an integrated spatial discrete model for simulating the thermal performance of the envelopes in building heating systems is developed The model is applied to simulate the thermal behavior of building envelopes, indoor air and heating terminals, and time constant of heat release processes are defined to characterize the flexibility potential of passive thermal storage units in building heating systems. The simulation results indicate that the thermal storage units in building heating systems related to a muti-time scale problem. The time constants for the heat storage units in heating systems with different terminals are different. During the heat release process, the time constant for radiator heating system reaches 180h–250h, the time constant fan coil heating system reaches 100h–150h. The time constant of heat release from walls in buildings is more than 120h. In the case of fan coil heating, the rate of increase of both room and wall temperatures is greater than in the case of radiator heating systems. The results of this study provide further data for developing better DR control strategies for heating systems with different building envelopes and heating terminals.
