Introduction

Taking mine ventilation as an example, after the fresh air from the ground is fed into the intake shaft, it supplies fresh air to the working face and also absorbs heat dissipation from the surrounding rock, mechanical equipment, coal oxidation, personnel, and other aspects. When the air is discharged from the return shaft, the temperature of the mine return air is much higher than that of the intake air. In addition, the mine return air has a large amount of low-temperature heat energy, which is not utilized and directly discharged into the atmosphere, It will cause great waste of thermal energy.