Efficient Energy Recovery with Wood Drying Heat Pumps

This article presents a 13-m3 wood dryer coupled with a 5.6-kW (compressor power input) heat pump. Drying tests with hardwood species such as yellow birch and hard maple were completed in order to determine the system's energy performance. Supplementary heating to compensate for the dryer heat losses was supplied using electrical coils or steam exchangers. The heat pump running profiles and dehumidification performance in terms of volumes removed and water extraction rates, coefficients of performance, and specific moisture extraction rates were determined for two all-electrical and two hybrid drying tests. The hardwood drying curves, share of the final moisture content, and final quality of the dried wood stacks, as well as total drying energy consumption and costs, were determined for each drying run. Finally, the total energy consumption of the drying cycles using a heat pump was compared with that of a conventional drying cycle using natural gas as a single energy source.

[1]  Vasile Minea,et al.  HEAT PUMPS FOR WOOD DRYING: NEW DEVELOPMENTS AND PRELIMINARY RESULTS , 2004 .

[2]  Hongwei Wu,et al.  Prediction of Timber Kiln Drying Rates by Neural Networks , 2006 .

[3]  Ivaldo Pontes Jankowsky,et al.  Review of Wood Drying Research in Brazil: 1984–2004 , 2006 .

[4]  Jonas Danvind,et al.  A Mass Transport Model for Drying Wood under Isothermal Conditions , 2007 .

[5]  V. Möttönen.  Variation in Drying Behavior and Final Moisture Content of Wood during Conventional Low Temperature Drying and Vacuum Drying of Betula pendula Timber , 2006 .

[6]  İlhan Ceylan,et al.  ENERGY AND EXERGY ANALYSIS OF TIMBER DRYER ASSISTED HEAT PUMP , 2007 .

[7]  Vasile Minea.  Improvements of high-temperature drying heat pumps , 2010 .

[8]  Shusheng Pang,et al.  Guest Editorial: Theoretical and Experimental Studies Leading to Improved Wood Drying Practice , 2008 .

[9]  Vasile Minea.  Energetic and Ecological Aspects of Softwood Drying with High-Temperature Heat Pumps , 2008 .

[10]  R. Keey,et al.  MOISTURE MOVEMENT ON DRYING SOFTWOOD BOARDS AND KILN DESIGN , 2002 .

[11]  C. G. Carrington,et al.  Impact of kiln losses on a dehumidifier drier , 1998 .

[12]  M. A. Stanish,et al.  Application of Wood Drying Simulation Models in Commercial Lumber Manufacturing , 2008 .

[13]  Arun S. Mujumdar,et al.  Global R&D Needs in Drying , 2007 .

[14]  Siaw Kiang Chou,et al.  HEAT PUMP DRYING: RECENT DEVELOPMENTS AND FUTURE TRENDS , 2002 .

[15]  Diego Elustondo,et al.  Energy Consumption in Industrial Drying of Radiata Pine , 2012 .

[16]  G. Lian-bai.  Recent Research and Development in Wood Drying Technologies in China , 2007 .

[17]  Ibrahim Dincer,et al.  Energy and exergy analyses of an industrial wood chips drying process , 2009 .

[18]  C. Carrington,et al.  Performance analysis of a dehumidifier using HFC134a , 1995 .

[19]  S. Pang.  Mathematical Modeling of Kiln Drying of Softwood Timber: Model Development, Validation, and Practical Application , 2007 .

[20]  C. Strumillo.  Perspectives on Developments in Drying , 2006 .

[21]  C. S. Kiang,et al.  Heat Pump Drying Systems , 2006 .