Energy saving by cooperative operation between district heating and cooling plant and building HVAC system

District heating and cooling (DHC) systems show a great potential for energy saving. However, a number of problems related to heating, ventilation, and air conditioning (HVAC) systems within a building resulted in an increase in energy consumption. The main reason is that the DHC plant and the building air conditioning systems are operated separately. This study proposes a new energy service in which the operator of the DHC plant controls air conditioning systems in the buildings simultaneously. Using a simulation model, it is found that energy conservation measures at the demand side would decrease energy consumption by 23.9%.