The term process heat is used in different senses. On the one hand, it refers to heat that is required for technical processes such as drying, melting or forging, and on the other hand to waste heat that is released during processes.
Process heat is usually divided into the following temperature ranges:Under 100 °C : Heat transport mostly with warm/hot water100 °C to 300 °C : Heat transport with hot water, steam or heat transfer oils (thermal oils)
Above 400 °C : e.g.: Melting furnaces for metals, ovens, drums or tunnels for drying processes, blast furnaces for steel production, industrial furnaces e.g. for annealing steel
The process heat is largely generated by combustion processes; waste heat from other processes can often be used as process heat. With an appropriate load profile throughout the year, the combined generation of electricity and heat is very economical and ecologically sensible. Combined heat and power (CHP) is generated using engine CHP, turbines or micro gas turbines. The Kombi Power System® developed by Gammel Engineering achieves the greatest possible efficiency and flexibility in terms of technologies, energy sources, heat transfer media and demand adjustment
Special solar collectors are also being used to provide process heat; however, their area of application is limited to drying processes, particularly in agriculture.
Sources : Wikipedia http://de.wikipedia.org/wiki/Prozessw%C3%A4rmeGammel Engineering / Regawatt
http://www.gammel.de/de/kombi-power-system/abwarmenutzungssysteme