Experimental study on cooling discharging characteristics of external melt ice-on-coil tanks in district cooling systems

External melt ice-on-coil thermal storage systems are usually used in large-scale district cooling systems (DCS) with advantages of technical stability, high instantaneous ice melting rate, low cooling temperature and low energy consumption of ice melting, which are good for the peak-shaving and valley-filling to the grid and the operation cost reduction. However, the ice melting and cooling discharging process is complex due to the water flow field, water temperature distribution, and inlet water temperature and flow rate, so the theoretical solution is more difficult to obtain. In this paper, the full-size ice storage tank of 255 MWh in the No.2 Plant of Qianhai DCS is studied, and the experimental research on the ice storage tank’s cooling discharging characteristics and temperature field changes is carried out in the early and peak cooling periods, respectively. The results show that there is a cubic relationship between the ice storage tank’s outlet temperature and the cumulative cooling discharging rate in the early and peak cooling periods. The findings of this study lend support to the design and engineering applications of external melt ice-on-coil systems.