A thermal-hydraulic coupled simulation approach for the temperature and flow rate control strategy evaluation of the multi-room radiator heating system

The lack of efficient temperature and flow rate control strategy is one of the key factors in excessive energy consumption of the district heating (DH) system. The current researches on secondary network simulation and control usually tackle the hydraulic characteristics of the network and building thermal dynamic separately. However, for the multi-room radiator heating system, the hydraulic characteristics and building thermal dynamics are coupled. An effective coupled thermal-hydraulic model for simulation and control of multi-room radiator heating systems is essential. In this paper, a novel thermal-hydraulic coupled simulation approach is proposed. The temperature distribution and thermal capacity of the radiator, as well as the hydraulic characteristics of the radiator heating network, are considered. A numerical method is developed to solve the proposed model. Different control strategies are analyzed based on the model. Result shows that efficient terminal flow rate control can save 8.4%–13% energy. The proportional control is superior to the on-off control in maintaining indoor temperature, while their energy consumptions are the same. Additionally, the hydraulic coupling effect of the network between households and floors should be considered if the balance valves are not installed on each floor.