Industrial Heating Information – Heat Recovery
The collection and re-cycling of what would be wasted or lost heat requires a lower temperature heat sink, where heat is captured and re-utilised.
Recovered heat can be used in a variety of ways:
- pre-heating of combustion air for boilers
- hot water generation, including pre-heating of boiler feed water
- pre-heating fresh air used to ventilate the building
- space heating
- power generation.
The following are potential sources of wasted heat:
- A boiler providing space heating or generating hot water
- Ventilation/air conditioning systems without any means of recirculation or heat recovery
- Water chiller or other cooling plant rejecting heat to outside
- Temperature stratification in high spaces (especially where warm air heaters or radiators are used in place of radiant heating)
Where any of the following processes exist, a thorough heat recovery evaluation should be undertaken:
- Boiler providing heat for any process
- Steam boiler blowdown
- Air compressors
- Hot exhaust air from dryers, etc.
- Flash steam
- Process cooling systems heat rejection
- Heat stored in products leaving the process
- Heat in gaseous and liquid effluents leaving the process
- Heat in cooling hydraulic oil systems