Energy flexibility for systems with large thermal masses with applications to shopping centers

In this paper we propose a scheme for managing energy flexibility in buildings with significant thermal masses and centralized climate control, such as commercial buildings, which can be used to provide ancillary services to the local electrical system (demand response). The scheme relies on being able to manipulate the forward flow temperature in the climate control system along with heating/cooling of zones of the building, and thereby controlling the electrical power consumption of the system. A Model Predictive Control law is formulated to provide pre-storage of thermal energy in the manipulated zones without violating comfort requirements. The scheme is illustrated on a case study of a Danish shopping center, from which actual heating/cooling data has been collected for identification of thermal dynamics. The Coefficient of Performance of the system's chiller is assumed to have a known dependence on flow and temperature, which is exploited to relate electrical power consumption to forward flow temperature. Simulation studies indicate potentials for significant power curtailment, in the order of 100 kW for one hour for the shopping center as a whole.