Why recover heat?
The question should in fact be: Why not recover heat? Amazingly, almost 100 percent of the electrical energy input to a compressor is converted into heat. 96 % of this energy can be recovered and reused for heating purposes.
Heat in the Compressor
Amazingly, almost 100 percent of the electrical energy input to a compressor is converted into heat.
The adjacent heat flow diagram (left) shows how this energy is distributed throughout the compressor system and how it can be recovered:
96 percent of the energy can be recovered for reuse, two percent remains in the compressed air and two percent radiates away from the compressor package into the ambient surroundings. So where does the usable energy in compressed air come from? The answer is actually quite simple and perhaps surprising: During the compression process and conversion of the electrical drive energy into heat, the compressor charges the air it draws in with energy potential. This corresponds to approximately 25 percent of the compressor’s electrical power consumption.
This energy is only usable however once the compressed air expands at its point of use and in so doing absorbs heat energy from the ambient surroundings. Of course the amount of this energy that is available for use depends on the pressure and leakage losses within the compressed air system.