In several industrial processes, e.g. drying within the forest industry, wet air and humid gas streams with a dew point of 40-60°C are usual. With the HyHeat hygroscopic technology these temperatures are upgraded in the absorption heat pump to process heat or district heating.
The process consists of the same subprocesses as shown in the Technology section. Depending on the customer’s requirements on the upgraded heat and the available driving energy (steam, flue gas etc.) different process designs result. The process design also has to consider required pre-treatment of the gas before entering the hygroscopic condenser. Any required pre-wash or filtering systems necessary are discussed outgoing from the specific industrial application.
During 2007 several applications in Pulp and Paper and sawmill industries were calculated on a pre-feasibility level, presenting processes for production of district heating as well as process steam. The economic assessment showed pay-back periods around and below 1.5 years under the specific conditions. Technical performance showed COP (coefficient of performance) values of around 1.7, meaning that two times the energy input in terms of required driving energy is produced.
The scale considered for industrial applications is around 5 MW of upgraded heat, but other scales can be discussed. Absorbents considered are the same as for the CHP solution.