Energetic and Ecological Aspects of Softwood Drying with High-Temperature Heat Pumps

Abstract

To provide short drying times, the Canadian softwood producers generally opt for drying at high temperatures (100–120°C). Industrial and laboratory-scale softwood dryers with high-temperature heat pumps have been developed and field-tested over the last few years in North America. Improvements in refrigeration circuits design, as well as in dehumidification speed and back-up heating controls, finally provided stable operating parameters of such advanced systems. This article shows that the energetic performances of softwood dryers with high-temperature heat pumps were as high as expected, and that a number of ecological impacts have to be considered.