Performance analysis of an improved temperature control scheme with cold stored in surrounding rock for underground refuge chamber

Abstract

This article proposed an improved temperature control scheme that combines mine compressed air, ice storage and surrounding rock, for mine refuge chambers. The feasibility of cooling mine compressed air via an ice storage unit was experimentally demonstrated, and the performance and temperature control performance of low-temperature mine compressed air on pre-cooling of surrounding rock were studied by numerical simulation. Results showed that: (i) The ice storage unit cools ventilation with a volume flow rate of 300 m3/h could be cooled to 20℃ from 35℃. For mine refuge chambers with an initial surrounding rock temperature of 35℃, the ambient temperature could be kept below 35℃ within 96 h, after pre-cooling the surrounding rock through continuously ventilating for 30 days at normal time. (ii) During pre-cooling, the surrounding rock temperature drops exponentially over time, and the temperature gradient decreases with ventilation rate and ventilation temperature, but has little to do with initial surrounding rock temperature. However the temperature of pre-cooled surrounding rock changes little when the ratio of ventilation time to non-ventilation time is 53:100 for mine refuge chambers with an initial surrounding rock temperature of 35 °C. (iii) For mine refuge chambers with an initial surrounding rock temperature of 32℃ or higher, the economy of the mine compressed air-ice storage-surrounding rock scheme will be reflected when the equivalent surrounding rock is 32℃ or lower.