Drying of solid, porous and hygroscopic materials is a complex and energy intensive process. About 85% of existing industrial dryers are convective dryers using hot air as a drying medium; they may consume up to 25% of the national industrial energy used in most of developed countries. Among other methods for reducing global energy consumption (electrical and fossil) in the drying industry there are heat pump dryers. First, this paper succinctly describes a high-temperature heat pump-assisted industrial-scale softwood dryer located in the Canadian cold climate, as well as the drying process, heat pump sizing principles and dryer energy estimation. Second, some control requirements aimed at matching the thermal capacities of the dryer-heat pump coupled system are proposed in order to improve system reliability and help increase the number of successful industrial implementations. Finally, several improved thermodynamic parameters and drying energy performance results obtained after implementation of the proposed control measures are provided.
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