A hierarchical scheme for balancing user comfort and electricity consumption of tank water heaters

Demand response (DR) programs offered by utility companies to residential consumers can negatively affect user comfort because of altering a regular operation of domestic devices. Advanced DR solutions need to account for flexibility of device usage in the form of energy savings that the customers can agree with. Specialized control schemes should inform utility companies about the level of such possible savings. This paper presents a hierarchical scheme that allows to control a domestic hot water storage system according to user comfort requests. The scheme uses a multi-objective optimization approach to interconnect comfort and electricity consumption of the tank water heater. The simulations show that the proposed control can not only significantly (by 95.6%) improve the user thermal comfort during hot water activities, but can also reduce energy consumption by 16.4% as compared to the weekly regular operation of the heater.