When heat pumps are used in drying, evaporation and distillation processes, heat is recycled within the process. The most common waste heat streams in industry are cooling water, effluent, condensate, moisture, and condenser heat from refrigeration plants. Because of the fluctuation in waste heat supply, it can be necessary to use large storage tanks for accumulation to ensure stable operation of the heat pump. Mainly electric closed-cycle compression heat pumps are used. This can be met by heat pumps.
Heat pumps can also be a part of an integrated system that provides both cooling and heating.
Mainly electric closed-cycle compression heat pumps are installed, but a few absorption heat pumps and heat transformers are also in use. Steam is used directly in industrial processes, and for heat distribution. The main applications are drying of pulp and paper, various food products wood and lumber. Drying of temperature-sensitive products is also interesting. Because the drying is executed in a closed system, odours from the drying of food products etc. are reduced.