Thermal model of an unconditioned, heated and ventilated seat to predict human thermo-physiological response and local thermal sensation

• Published in: Building and environment Vol. 169; p. 106571
• Main Authors: Fojtlín, Miloš, Psikuta, Agnes, Fišer, Jan, Pokorný, Jan, Toma, Róbert, Annaheim, Simon, Jícha, Miroslav, Rossi, René M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2020; Elsevier BV
• Subjects: Bias; Computer simulation; Conditioning; Cooling effects; Environmental conditions; Fiala model; Heat flux; Heating; Human; Physiology; Seat; Seats; Skin temperature; Test procedures; Thermal analysis; Thermal diffusivity; Thermal sensation; Thermo-physiology; Ventilation; Human; Seat; Heating; Thermal sensation; Ventilation; Thermo-physiology; Fiala model
• ISSN: 0360-1323; 1873-684X
• DOI: 10.1016/j.buildenv.2019.106571

Local conditioning technologies such as seat heating and ventilation have been shown to improve thermal sensation and comfort, with reduced energy demands compared to conventional methods of heating and cooling. Investigation of the conditioning effectivity is demanding in terms of time and resources, as it is mainly based on human subject or thermal manikin testing. One promising method of rapidly investigating a wide range of environmental conditions is thermo-physiological and thermal sensation modelling. Until now, however, one of the most important properties of the seat, its thermal diffusivity, has been neglected in such simulations. We therefore developed a methodology that involves one-dimensional, thermal model of the seat coupled with a multi-node thermo-physiological model and thermal sensation models. The seat thermal model showed realistic predictions of heat flux in the seat contact interface for control (no conditioning), heated, and ventilated seats. The modelling results were validated against our original experimental data and data from the literature for unconditioned, heated, and ventilated seats. The root mean square deviation (RMSD) and bias of the local skin temperatures were within the standard deviation of the measurement, typically within 1 °C. In the case of the predicted local thermal sensations, we found the RMSD and bias to be below two standard deviations of the human votes in two out of three of the thermal sensation models examined. Less accurate predictions were found for the seat contact, where further model refinement is needed. •A model was developed to calculate heat exchange between a seat and its occupant.•A novel approach was applied to simulate effects of heated and ventilated seats.•The scope comprises investigation of thermo-physiology and thermal sensation.•The methodology was validated against our own experimental and literature data.•The findings are applicable in designing of comfortable, energy-efficient indoor spaces.