Research PaperDischarging performance of a forced-circulation ice thermal storage system for a permanent refuge chamber in an underground mine

•Thermal analysis of an ice thermal storage system for a permanent refuge chamber.•Experimental measurements used to provide and validate a correction factor.•Correlation developed between transient discharging power and remaining ice fraction.•Minimum cooling requirement satisfied via automatic control through correlation.•Operational duration of system maximized via automatic control.

This study aimed to develop a proper control strategy for a forced-circulation ice thermal storage system (ITSS) designed for a permanent refuge chamber with an accommodation capacity of 50 persons. The heat transfer characteristics of the ITSS were investigated through theoretical and experimental approaches. A quasi-steady one-dimensional mathematical model for predicting the transient discharging power was proposed. On this basis, a control strategy was proposed to fulfill the minimum cooling requirement in consideration of both effective discharging time and human comfort. The minimum required velocity of the ITSS was analyzed; from this, the effective working time of the ITSS was determined to be 64.57 h. Additionally, the heat load inside the chamber was found to be the main factor that affected the effective temperature control duration and the utilization ratio of the ice. Thus, a reserve factor, which is defined as a function of rated heat load and determined by the discharging performance model, is suggested for consideration during optimization.