Underground coal mines use local, direct cooling machines with cooling power of 150-450 kW for air-conditioning work areas in headings, tunnels and longwalls.
In the direct cooling machine the evaporator is used as an air-cooler and cools directly the surrounding air. The air flowing through the evaporator is cooled by 10-14oC from a temperature above 26oC.
The water from condenser cooling circuit of the direct cooling machines is cooled down in evaporator-type water coolers installed within the return air-stream. Alternatively an open cooling method can be used i.e. the condenser is cooled directly with the water from underground water pipeline.
The local, direct cooling machine consists of:
- aggregate with compressor, electric motor and condenser,
- evaporator – air-cooler,
- condenser-cooling water circuit (open or closed with evaporator-type water cooler).
