Eliminating early cut-offs and estimating cycle end time in a tumble dryer

Abstract

Modern domestic clothes dryers contain sensors which attempt to detect when the load is dry, and subsequently, when the drying process should be ceased. However, due to a range of factors, occasionally the dryer may cut-off earlier than is desired. At a recent mathematics-in-industry study group workshop in New Zealand (MINZ-2015), Fisher and Paykel presented the challenge of eliminating these early cut-offs. Using a statistical fitting technique which accounts for stochastic noise and utilises confidence intervals, we outline a more rigorous procedure for detecting the end state of the drying process. We analyse experimental data provided at the workshop and investigate the possibility of estimating drying cycle end time in advance. Finally we interrogate the experimental data to estimate physical drying parameters which may be used in a reaction engineering drying model. References C. Marsh and A. Wilkins, Determining temperature control of wash water in a laundry environment. Proceedings of the 2005 mathematics-in-industry study group 163–208, 2005. C. Marsh, S. Taylor, P. Milliken and G. Senaratne, Developing an understanding of washing machine dynamics. Proceedings of the 2006 mathematics-in-industry study group 133–152, 2007. X. D. Chen, The basics of a reaction engineering approach to modeling air-drying of small droplets or thin-layer materials Drying Technology 26 , 627–639, 2008. doi:10.1080/07373930802045908 X. D. Chen and A. Putranto, Modelling Drying Processes: A Reaction Engineering Approach , Cambridge University Press, 2013. ISBN 978-1-107-01210-3 doi:10.1017/cbo9780511997846 R. B. Keey, Drying of Loose and Particulate Materials , Hemisphere Publishing Corporation, 1992. ISBN 0-89116-878-8 doi:10.1080/07373939208916507 A. K. Haghi, Heat and Mass Transfer in Textiles . WSEAS Press, 2011. ISBN 978-1-61804-025-1 A. Putranto, X. D. Chen, S. Devahastin, Z. Xiao, and P. A. Webley, Application of the reaction engineering approach (rea) for modeling intermittent drying under time-varying humidity and temperature. Chemical Engineering Science , 66(10):2149–2156, 2011. doi:10.1016/j.ces.2011.02.025 A. Putranto, X. D. Chen, and P. A. Webley, Modeling of drying of food materials with thickness of several centimeters by the reaction engineering approach (rea). Drying Technology , 29(8):961–973, 2011. doi:10.1080/07373937.2011.557793 A. Putranto, X. D. Chen, Z. Xiao, and P. A. Webley, Modeling of high-temperature treatment of wood using the reaction engineering approach (rea). Bioresource technology , 102(10):6214–6220, 2011. doi:10.1016/j.biortech.2011.02.053