24 June 2014

High-Temperature Heat Pumps Used for Low-Grade Industrial Process and Waste Heat Recovery


Industrial low-grade process and/or waste heat sources are abundant Canada as well as in many other countries. Such sources, especially those available at lowtemperatures
going from -5 °C to about 45 °C, are rarely recovered in order to improve the
overall efficiency of industrial energy intensity and productivity, and to reduce the global greenhouse gas emissions. This paper summarizes a part of Canada’s contributions to
Tasks 3 and 4 of the IEA-IETS Annex 13/IEA-HPP Annex 35 project. It succinctly presents a number of heat pump systems able to supply process or domestic hot water at temperatures
up to 85 °C or hot air up to 95 °C (in the case of high-temperature drying heat pumps) by recovering low-grade energy from various process and waste heat sources. Small-scale prototypes have been laboratory designed, built and experienced in order to validate the
refrigerant choice and simulated performances, and to improve the systems’ control sequences and reliability. In the case of natural refrigerants as ammonia and CO2, additional objectives aimed at forming and training local expertises, testing and improving the safety measures according to the Canadian national refrigeration code and increasing the
confidence of refrigeration specialists, industrial plant owners and general public. A part of laboratory and in-field, or simulated results obtained, intending at preparing and encouraging
future implementations in various industrial and institutional facilities, are also succinctly presented.