Proposed liquid CO₂ cycle refrigeration system for heat hazard control

¹ College of Safety Science and Engineering, Xi’an University of Science and Technology, 710054 Xi’an, China
² Shaanxi Key Laboratory of Prevention and Control of Coal Fire, 710054 Xi’an, China

^* Corresponding author: xy1235813@sina.com

Abstract

Liquid CO₂ can absorb heat via phase change and generates cryogenic CO₂ which can effectively solve the problem of thermal damage in the deep coal mining process. The CO₂ cycle refrigeration device system is designed to effectively cool down the working surface of the mine in which CO₂ is cyclically utilized. COMSOL Multiphysics simulation software is used to characterize the CO₂ cycle refrigeration system in mine of the heat transfers process between CO₂ and the air flow in tunnel. The results show that the reduction of steady air flow temperature reach at 8 °C in the tunnel by CO₂ cycle refrigeration system before the air flow into work face. we analyzed the influence of main parameters on refrigeration system and gets the results:1) The refrigeration system get higher cooling efficiency of cryogenic CO₂ when the ventilation velocity of local fan is increased, and the temperature of outlet CO₂ and steady air flow in tunnel has increased; 2) Increasing the CO₂ flow, the refrigeration effect of the system is enhanced obviously, but CO₂ refrigeration capacity utilization ratio is reduced; 3) Increasing the length of helical tube would led to use CO₂ refrigerating capacity more efficiently; 4) The cooling effect of the cooling system can be improved obviously by lowering the the CO₂ cooling temperature.