Coordinated scheduling of thermostatically controlled real-time systems under peak power constraint

A substantial fraction of the energy demand of buildings comes from air-conditioners (ACs), refrigerators, etc., which do not need human interaction for their continuous operations. So long as desirable temperature levels, which we refer to as thermal comfort-bands, are maintained by such background loads, users will not be concerned about when they perform their assigned functions. i.e., when they consume the energy required to function. This paper addresses the problem of maintaining thermal comfort-bands associated with background loads under Peak energy consumption constraint. Based on our empirical observations pertaining to energy consumption profiles of thermal comfort-band maintaining ACs, a) we present a feasibility criterion for maintaining the thermal comfort-band of a given set of background loads under constraints on the peak available power and (b) we propose TCBM, a new algorithm for scheduling such background loads under peak power constraint. In addition to limiting peak power demand, the TCBM algorithm avoids undesirable switching (ON and OFF) of electrical appliances to improve efficiency of the equipment and reduce failures. Results from simulation and real-life implementation demonstrate that our algorithm is superior to the existing work on background load scheduling. We also show how TCBM can adapt to changes in ambient parameters and provide the basis for efficient demand-response systems.