Analysis of effective energy consumption of chilled water transportation of external pipe network in district cooling systems

The boundary between the external pipe network and the chiller plant of the district cooling system (DCS) is clearly defined, and the effective power consumption of the external pipe network and the power consumption of the secondary pumps are compared. An analysis method is developed for evaluating the effects of energy consumption of chilled water transportation in pipe network of DCS. Based on the actual operating data of Qianhai DCS Plant 2, the impact of energy consumption of chilled water transportation in pipe network of DCS energy efficiency is analysed according to different time scales (year, month, hour). The results show that at full occupancy rate, the power consumption to heat supply ratio of the pipe network is approximately 0.007. For a DCS with a chiller’s COPRof 5, the impact of energy consumption of chilled water transportation in pipe network on the system COPDCSis -4.2%. The cooling energy process in a DCS may be transported by equipment such as ethylene glycol pumps, ice melting pumps, primary chilled water pumps, and secondary chilled water pumps, all of which have an equal impact on the system energy efficiency. Reducing the energy consumption of cooling energy transportation within the chiller plant holds significant potential for improving the system’s energy efficiency.