Space heating demand response potential of retrofitted residential apartment blocks

In future and smarter energy systems, time varying energy prices enable indirect demand response (DR) to assist the electricity supply system to meet demand. This simulation-based study investigates how economic model predictive control (E-MPC) schemes for space heating operation can utilize the thermal mass in an existing multi-story apartment block and eight retrofit scenarios to provide DR. The performance of the E-MPC scheme was evaluated in terms of its ability to enable end-user cost savings, reduce CO2 emissions and to perform load shift of the heating demand compared to a conventional PI controller. Two E-MPC approaches were considered: centralized E-MPC where inter-zonal effects were considered and decentralized E-MPC that neglected heat transfer between adjacent apartments. The E-MPC schemes led to increasing cost savings (up to approx. 6%) and reduced CO2 emissions (up to approx. 3%) as a function of increasing energy efficiency of the retrofit scenarios. The absolute amount of shifted power from peak load periods was rather consistent (approx. 2 kWh/m2 heated net area) across all retrofit scenarios compared to the existing building. The centralized E-MPC scheme led to marginally better results than the decentralized E-MPC. The added complexity involved in establishing a centralized E-MPC compared to a decentralized E-MPC may therefore not be worth the effort.