Potential for using thermal storage in an apartment building to enable low-carbon heating

Abstract

Buildings account for a significant proportion of global CO2 emissions, with heating as a major contributor. The sources of energy for heating vary in their carbon intensity over time. By using the thermal storage capacity of apartment buildings with concrete structures, it is possible to shift the timing of heating demand. This study evaluates how much CO2 emissions can be saved by actively controlling the building’s heat output based on forecast of future CO2 intensity in the energy supply. A typical Swedish concrete apartment building equipped with advanced control systems and energy monitoring was used to enabling accurate calibration of the digital energy simulation model. A control strategy was developed based on three parameters: a setpoint for whether heat should be charged or discharged, a forecast horizon indicating how far into the future the CO2 intensity of the energy supply is considered, and a threshold defining the minimum change in CO2 intensity required to trigger control actions. The reduction in heating-related CO2 emissions depends on the variation in the energy supply. The study shows that a building that use electricity, produced in Sweden and imported from other countries, as heating source can reduce heating-related CO2 emissions by 18 percent without significantly affecting indoor climate by using the thermal storage capacity. Effective control requires a CO2 intensity forecast 10–24 hours ahead in the energy supply.