DESIGN OF SOLAR-DEHUMIDIFICATION WOOD DRYING KILN CHARACTERIZED BY HIGH CAPACITY AND TEMPERATURE

摘要

Solar-dehumidification wood drying kilns attract more and more interest due to their energy saving characteristics. However, such dryers are only available for small effective drying volume capacities, less than 30 m~3, and for low drying temperature under 65℃, for Chinese domestic products. In fact, wood drying kilns over 60 m~3 and high drying temperatures upto 95℃ or even higher are commonly desired from economic and process technology points of view. For instance, if the drying temperature is below 60℃, a long drying period will result in high operational costs and may also cause mould as well colour changes on the lumber surface. It is also known that the anti-decay ability of the seasoned lumber is thus reduced. As such, the design of the solar-dehumidification wood drying kiln with an effective drying volume capacity of 60 m~3 and a drying temperature upto 95℃ was made. Two compression processes for dehumidification and heat pump systems were adopted. The refrigerant of R_(142b) which has low RODP and RGE, was utilized as the actuating medium. The values of COP, PER and SMER were 4.42, 1.19 and 3.08 kg (H2O)/(kWh) for the dehumidification system. The values of COP and PER were 3.05 and 0.824 for the heat pump (heat supply) system. The averaged total COP and PER over the both were 3.74 and 1.01 respectively.