Paper Title
Operation Practice of Reducing Return Water Temperature of Primary Network in Long-Distance Heating Project

Long distance heating with large temperature difference is an effective solution to solve the problem of increasing urban heating area and insufficient pipe network transmission capacity. After commissioning and operation in a heating season, the operation practice of reducing the return water temperature of the primary network is summarized. Absorption type large temperature difference heat pump unit is the core equipment to realize large temperature difference heating. Through the data analysis of three central stations, when the primary inlet water temperature reaches more than 95 ℃, the primary return water temperature is significantly reduced. The hydraulic balance adjustment of the secondary side of the heat pump station shall be adjusted according to the imbalance degree. Reduce the loss of scheduling at the secondary side of the heat pump, and the return water temperature at the primary side also decreases. When the flow at the primary and secondary sides of the pressure isolating station plate is similar, the heat exchange end difference is small. Therefore, during operation, make the secondary side flow of the pressure isolation station close to the primary side flow as much as possible, so that the large temperature difference absorption heat pump is in the efficient operation range. Keywords - Long Distance Heating with Large Temperature Difference, Absorption Heat Pump Unit, Return Water Temperature of Primary Network, Loss of Dispatch, Flow Ratio.