Modeling of thermal energy sharing in integrated energy communities with micro-thermal networks

This investigation focuses on the potential of harvesting heat rejected from the cooling and refrigeration systems of buildings with high year-round cooling and refrigeration demand (e.g., ice arenas and grocery stores) and using it to heat other nearby buildings. Integrating a small group of buildings with diverse thermal demands via a low-temperature micro-thermal network effectively allows wasted thermal energy to be harvested and shared among the buildings with minimal thermal and mechanical losses. This paper presents a reduced model that shows the potential of harvesting thermal energy between buildings by calculating the amount of heat energy simultaneously shared between the connected buildings on a five-minute time resolution. The model also evaluates changes in greenhouse gas (GHG) emissions and the amount of energy that is still required from supplemental heating sources after harvesting relative to conventional stand-alone building systems. This study shows that changing the operating temperature of the micro-thermal network when primarily sharing between diverse thermal demand buildings has a minor effect on GHG emissions but can have a larger effect on electrical energy consumption. The model is applied using actual utility energy consumption at one of the potential clusters in Ontario, with results showing that approximately 48% of the cluster's total heating requirements can be covered by instantaneous sharing between buildings, and an additional 12% can be covered by daily short-term thermal storage. This reduced heating demand results in an approximately 74% reduction in total GHG emissions.