Most Industrial Heat Is Low-Grade
Surveys show the majority of recoverable industrial heat sits below 200 degrees C. Low-grade heat is harder to use directly, but several routes recover it economically.
Recovery Routes
- Air preheat: an air-to-air plate exchanger feeds warm air back to the process, cutting fuel use.
- Absorption chillers: drive cooling from waste heat instead of electricity.
- ORC: generate power when a stable stream above about 150 degrees C exists.
- Heat pumps: upgrade low-grade heat to a useful temperature for heating networks.
Where Air-to-Air Fits
For exhaust below 200 degrees C, a sensible plate air-to-air heat exchanger recovers energy with no moving parts and minimal maintenance. In food and pharma lines the exchanger must be isolated, with no recirculation of exhaust into supply air.
Low-grade heat is rarely worth a dedicated power block on its own. Combining preheat, chilling, and a heat pump usually beats a standalone generator on payback.