Waste heat utilizing device for air compressor

A waste heat utilization device for an air compressor, comprising:

• an air compressor;
• a discharge path of the air compressor;
• a circulation path along which a low boiling point medium circulates;
• an evaporator interposed on the discharge path and the circulation path to evaporate the low boiling point medium by performing heat exchange between the low boiling point medium and at least one of compressed air discharged from the air compressor or lubricating oil included in the compressed air;
• an expansion machine into which the low boiling point medium evaporated by the evaporator is introduced such that a rotary force is applied thereto by the low boiling point medium;
• and
• a condenser that cools and condenses the low boiling point medium discharged from the expansion machine,
• a circulation pump interposed on the circulation path to circulate the low boiling point medium;
• and a branch passage that bifurcates from the discharge path and is connected to the circulation pump, wherein:
• a power consumption of the air compressor is reduced by the rotary force generated in the expansion machine, and the compressed air is introduced into the circulation pump from the branch passage such that the circulation pump is driven by the compressed air.