From the organizational point of view, there are two ways to utilize waste heat: internally and/or externally.
- Internal waste heat utilization can be carried out in three steps:
- Before a company starts with the utilization of waste heat, it should reduce the heat losses with thermal insulation improvements and process optimization.
- As a second step, the company should reintegrate the waste heat into production processes by waste heat recovery or by using it for the building’s heat supply.
- The third step involves the waste heat transformation into other useful energy forms, such as electricity (by Organic Rankine Cycle (ORC)) or thermal cooling (by absorption and adsorption cooling plants).
- Another option is the cross-company waste heat utilization, meaning that the waste heat that can’t be used internally can be used by third parties, in commercial or residential buildings for example. Key challenges for this option lie in access to reliable data to match the waste heat potential and demands, and the fact that these do not always match.
Currently the most economically feasible utilization of waste heat requires spatial proximity of the waste heat source and demand. The most flexible form of energy conversion seems to be electricity that is easily transportable or can be exported to the utility company. However low technology efficiency in electricity generation from waste heat is still a barrier that needs to be better addressed.
Iconographs © Deutsche Energie-Agentur (dena)