CALCULATION OF THE THERMAL ENERGY AND ITS COMPONENTS REQUIRED FOR THAWING LOGS
Keywords:
frozen logs, frozen bound water, frozen free water, thawing, thermal energyAbstract
An approach for calculating the thermal energy and its components required for thawing logs intended for veneer production is proposed. The approach is based on the use of two personal mathematical models. The influence of all combinations between 5 values of the initial wood temperature from −1 °C to −40 °C and 3 values of the wood moisture content above the hygroscopic range (0.4 kg·kg-1, 0.6 kg·kg-1, and 0.8 kg·kg-1) on the thermal energy and its four components required to thaw beech logs with a diameter of 0.4 m at operating temperature of the heating medium of 80 °C was investigated. The obtained results show that this energy changes in the range from 31.66 kWh·m-3 (at −1 °C and 0.4 kg·kg-1) to 95.36 kWh·m-3 (at −40 °C and 0.8 kg·kg-1). The approach could be applied to determine the energy required to thaw various frozen capillary-porous materials in practice.
References
Câmpean, M., 2005. Heat Treatments of Wood. Transilvania University of Braşov, Braşov, Romania, 199 pp.
Chudinov, B. S., 1968. Theory of the Thermal Treatment of Wood. Nauka, Moscow, 255 pp.
Deliiski, N., 2003. Modelling and Technologies for Steaming Wood Materials in Autoclaves. Dissertation for DSc., University of Forestry, Sofia, 358 pp.
Deliiski, N., 2004. Modelling and Automatic Control of Heat Energy Consumption Required for Thermal Treatment of Logs. Drvna Industrija, 55(4), 181199.
Deliiski, N., 2009. Computation of the 2-dimensional Transient Temperature Distribution and Heat Energy Consumption of Frozen and Non-Frozen Logs. Wood Research, 54(3), 67−78.
Deliiski, N., 2011. Transient Heat Conduction in Capillary Porous Bodies. Ahsan A. (ed.) Convection and Conduction Heat Transfer. Tech Publishing House, Rieka, Croatia, 149-176, https://doi.org/10.5772/21424
Deliiski, N., 2013a. Computation of the Wood Thermal Conductivity during Defrosting of the Wood. Wood Research, 58(4), 637650.
Deliiski, N., 2013b. Modelling of the Energy Needed for Heating of Capillary Porous Bodies in Frozen and Non-Frozen States. Lambert Academic Publishing, Scholars’ Press, Saarbrücken, Germany, 106 pp., http://www.scholars-press.com//system/covergenerator/build/1060
Deliiski, N., Dzurenda, L., 2010. Modelling of the Thermal Processes in the Technologies for Wood Thermal Treatment. Technical University in Zvolen, Slovakia, 224 pp.
Deliiski, N., Dzurenda, L., Angelski, D., Tumbarkova, N., 2018. An Approach to Computing Regimes for Autoclave Steaming of Prisms for Veneer Production with a Limited Power of the Heat Generator. Acta Facultatis Xylologiae Zvolen, 60(1), 101-112, https://doi.org/10.17423/afx.2018.60.1.11
Deliiski, N., Dzurenda, L., Tumbarkova, N., Angelski, D., 2020a. Mathematical description of the latent heat of bound water in wood during freezing and defrosting. Acta Facultatis Xylologiae Zvolen, 62(1), 41-53, https://doi.org/10.17423/afx.2020.62.1.04
Deliiski, N., Dzurenda, L., Tumbarkova, N., 2020b. Modelling of the Two-Dimensional Thawing of Logs in an Air Environment. In Valdman J. (ed.). Modelling and Simulation in Engineering – Selected Problems, Intech Open, London, 19 pp.
Deliiski, N., Dzurenda, L., Niemz, P., Angelski, D., Tumbarkova, N., 2021. Computing the 2D Temperature Distribution in Logs Stored for a Long Time in an Open Warehouse in Winter and during Subsequent Autoclave Steaming. Acta Facultatis Xylologiae Zvolen, 63(1), 49-62, https://doi.org/10.17423/afx.2021.63.1.05
Dorn, W.S., McCracken, D. D., 1972. Numerical methods with FORTRAN IV: Case Studies, John Willey & Sons Inc., New York.
Dzurenda, L., Deliiski, N., 2019. Thermal Processes in the Woodworking Technologies. Technical University in Zvolen, Slovakia, 283 pp.
Hadjiski, M., 2003. Mathematical models in advanced technological control systems. Automatics & Informatics, 37, 7-12.
Khattabi, A., Steinhagen, H. P., 1992. Numerical Solution to Two-dimensional Heating of Logs. Holz als Roh- und Werkstoff, 50 (7-8), 308-312.
Khattabi, A., Steinhagen, H. P., 1993. Analysis of Transient Non-linear Heat Conduction in Wood Using Finite-difference Solutions. Holz als Roh- und Werkstoff, 51 (4), 272-278, https://doi.org/10.1007/BF02629373
Khattabi, A., Steinhagen, H. P., 1995. Update of “Numerical Solution to Two-dimensional Heating of Logs”. Holz als Roh- und Werkstoff, 53(1), 93-94.
Kollmann, F. F. , Côté, W. A. Jr., 1984. Principles of wood science and technology. I. Solid wood. Springer-Verlag, New York, Berlin, Heidelberg, 592 pp.
Lawniczak, M., 1995. Hydrothermal and plasticizing treatment of wood. Part I. Boiling and steaming of wood. Agricultural Academy, Poznan, 149 pp.
Mörath, E., 1949. Das Dämpfen ubd Kochen in der Furnier- und Sperrholzindustrie. Holztehnik, No. 7.
Niemz, P., Teischinger, A., Sandberg, D. (Eds.), 2023. Springer handbook of wood science and technology. Springer Nature Switzerland AG, Cham, 2069 pp.
Pervan, S., 2009. Technology for Treatment of Wood with Water Steam. University in Zagreb, Zagreb, Croatia.
Shubin, G. S., 1990. Drying and Thermal Treatment of Wood. Lesnaya Promyshlennost, Moscow, 337 pp.
Sohor, M., Kadlec, P., 1990. Hydrothermal treatment of wood for production of veneer. Drevo, № 2.
Steinhagen, H. P., 1986. Computerized Finite-difference Method to Calculate Transient Heat Conduction with Thawing. Wood Fiber Science, 18 (3), 460-467.
Steinhagen, H. P., 1991. Heat Transfer Computation for a Long, Frozen Log Heated in Agitated Water or Steam – A Practical Recipe. Holz als Roh- und Werkstoff, 49 (7-8), 287-290, https://doi.org/10.1007/BF02663790
Steinhagen, H. P., 2005. Veneer block conditioning manual for veneer and plywood production. Maderas. Cienciay Tecnología, 7 (1), 49–56.
Steinhagen, H. P., Lee, H. P., Loehnertz, S. P., 1987. LOGHEAT: A Computer Program of Determining Log Heating Times for Frozen and Non-Frozen Logs. Forest Products Journal, 37 (11-12), 60-64.
Trebula, P., Klement, I., 2002. Drying and Hydrothermal Treatment of Wood. Technical University in Zvolen, Slovakia, 449 pp.
Tumbarkova, N., 2019. Modelling of the Logs’ Freezing and Defrosting Processes and their Energy Consumption. PhD Dissertation, University of Forestry, Sofia, Bulgaria, 198 pp.
Videlov, H., 2003. Drying and Thermal Treatment of Wood. University of Forestry, Sofia, 335 pp.
