A Study On Contral Strategy For District Heating And Cooling System Using River Sourced Heat PUMPS

In this paper a simulation study has been made for developing operation strategies for the river water sourced heat pumps. Focused on cooling mode, the temperature differences between the water inlet and outlet of the condensers were used as the control parameter to reduce the system energy consumption. Control algorithms have been developed for modulating water pumps, heat pump systems based on building air conditioning load.Is obtained by the DeST software simulation:regional architecture maximum cooling load is 10836 kW, the maximum heat load is 4740 kW. During cooling, the building air conditioning load rate within 70%～80% in time of the maximum cooling time (11.92%), building air conditioning load rate within 90%～100% in the time of the minimum cooling time (2.41%). During heating, with the increase of building air conditioning load rate, heat pump running time gradually reduce.Using the program compiled by the author to calculate heat pump condenser best import and export temperature difference and heat pump and river water pump energy saving operation strategy is put forward. The results are as follows:● Building air conditioning load rate within 0%-9%, running one heat pump and one pump.● Building air conditioning load rate within 10%～20%, the heat pump condenser best import and export temperature difference is 3℃, running one heat pump and one pump. Heat pump load rate range is 0.35～0.64.● Building air conditioning load rate within 21%-35%, the heat pump condenser best import and export temperature difference is 6℃, running one heat pump and one pump. Heat pump load rate range is 0.64-0.95.● Building air conditioning load rate within 36%-42%, the heat pump condenser best import and export temperature difference is 6℃, running two heat pumps and one pump. Each heat pump load rate range is 0.55～0.68.● Building air conditioning load rate within 43%～65%, the heat pump condenser best import and export temperature difference is 6℃, running two heat pumps and two pumps. Each heat pump load rate range is 0.68-1.00.● Building air conditioning load rate within 66%～100%, the heat pump condenser best import and export temperature difference is 7℃, running three heat pumps and two pumps. Each heat pump load rate range is 0.65～0.90.● More than one pump parallel operation, the pump running operating frequency is the same.The energy consumption of the Heat pump condenser adopting variable flow operation is slightly higher than adopting constant flow operation (0.56%). However, the energy consumption of the pump with variable flow operation is lower than using constant flow operation (46.6%). The energy saving rate of the system adopting variable flow operation is 5.26%.