Dehumidification drying of red oak. Part 2. Cause of cooling coils corrosion in heat pumps

Dehumidification kiln-drying of red oak lumber resulted in the corrosion of cooling coils in a laboratory kiln. Cooling coils in industrial kilns prot ected by anti-corrosion finishes did not exhibit any signs of corrosion. La boratory kiln-drying condensates were characterized by a bluish tinge and p roduced blue crystals upon evaporation. X-ray diffraction analysis of the k iln condensate blue crystals identified them as copper acetate monohydrate. This identification was further supported by Fourier transform infrared an d UV-visible spectra of condensate crystals.