Multistage cooling system for temperature reduction of the working face in deep coal mines: A technical-economic evaluation

Workers in deep coal mines are often exposed to hyperthermal conditions, which is a health and safety hazard. Although many novel approaches have been proposed in recent years, air distribution optimization combined with thermal analysis based on existing cooling systems has rarely been conducted. Here, heat dissipation in the deep mine environment was estimated based on field measurements and numerical simulations. A pilot study was conducted to validate the performance of the multistage cooling system and optimize the distribution ventilation. The results show that the “2 + 3” layout (Two air cooler outlets are in the machine lane, and three air cooler outlets are in the open-off cut) was superior to other schemes in terms of the temperature field and energy consumption. In addition, the outlet air temperature should be set to ≤20 °C, and the air volumetric flowrate of the longest outlet should be > 400 m3/min to improve the thermal environment of the wind lane. This effectively reduces the average temperature of the entire working face by 4.6–5.1 °C compared to the situation without cooling measures, thereby increasing the comfortable zone of the working face (