Building energy and thermo-hydraulic simulation (BETHS) for district heat system in residential communities: A case of Shenyang, China

District Heating Systems (DHS) have received renewed attention in relation to their environmental, economic, and health benefits. Research literature on DHS tends to focus separately, either on the thermo-hydrological modelling or building energy demand. Rarely are there combined simulation approaches that consider the interactions between the district heating system and the buildings they serve. There is a practical need for a coupled simulation model to inform operation and energy retrofit strategies, such as, building insulation, water leakage prevention, and achieving comfortable indoor air temperatures. In this study, a novel simulation model, BETHS, is developed to predict the time-varying energy performance and occupant thermal comfort of a cluster of buildings served by a DHS in the urban context. The simulation results are compared with field measurement data collected for a secondary network consisting of 12 buildings and 2788 m of pipeline network over a 10-day period, in Shenyang, Liaoning, China. Predicted water temperature and indoor air temperature showed reasonable agreements with measured data. Simulation results suggested an energy saving of 35% for improved building insulation, 32% for switching from coal to gas, 18% for reduced indoor temperature, 14% for water leakage prevention, and 67% if all are combined. The BETHS model can be a valuable extension to a building energy simulation framework, and support retrofit strategies and operational decisions for existing DHS networks.