Dynamic optimization of control setpoints for an integrated heating and cooling system with thermal energy storages

Abstract

Energy systems for buildings and neighborhoods are expected to become more complex and flexible. Advanced control strategies are required to exploit the full potential of this flexibility and are especially important for systems with storages. In this study, the control of an integrated heating and cooling system for a building complex in Oslo, Norway, was analyzed. Focus was on the control setpoints for the main heat pumps, which had a total heating capacity of about 1 MW and were connected to thermal storage tanks. Previously developed simulation models of the system and its main components were made suitable for dynamic optimization with long time horizons. JModelica.org was used to find optimal control trajectories for the system with two different objectives. The first objective was to reduce the electricity use of the system and the second objective was to reduce the electricity costs of the system. The results showed that the electricity use of the system could be reduced by about 5% for the analyzed year. The electricity costs could be reduced by about 5–11% for the three analyzed winter months, depending on the variability of the electricity price and the size of the storage tanks.