Most of the electrical energy a compressor consumes is converted into heat rather than compressed air. In oil-injected screw machines, much of that heat is carried away by the oil and cooling air. A heat recovery system captures it and puts it to useful work instead of venting it outdoors.
What can be recovered
- Hot water for washing, process and pre-heating
- Space heating for workshops and warehouses
- Pre-heating boiler feed water
- Drying and other low-temperature processes
Typical savings
A well-designed heat recovery system can reclaim 50–90% of the compressor input energy as usable heat. For a plant running large compressors around the clock, that frequently cuts water-heating costs enough to pay for the recovery equipment within one to two years.
Design considerations
Heat recovery works best where there is a steady heat demand close to the compressor room. The system should not raise the compressor cooling temperature beyond the manufacturer limit, and it must include controls so recovered heat never disrupts compressor operation.