Optimal operation of energy storage in buildings: Use of the hot water system

We consider the optimal operation of energy storage in buildings with focus on the optimization of an electric water heating system. The optimization objective is to minimize the energy costs of heating the water, with the requirement that we should satisfy the uncertain demand at any time. The main complications in this problem are the time varying nature of the electricity price and the unpredictability of the future water demand. In this paper we use the water heating system as an example for formulating a general framework which could easily be applied to similar problems with energy storage capacity. Feasibility and optimality are discussed and the main points are illustrated in the simulation case studies.