2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
SINGLE-SECTOR THERMOPHYSIOLOGICAL HUMAN SIMULATOR
FOR CLOTHING RESEARCH
Agnieszka Psikuta 1,2 , Mark Richards 1 and Dusan Fiala 2,3
1 Laboratory for Protection and Physiology, EMPA Swiss Federal Laboratories for Materials
Testing & Research, St. Gallen, Switzerland
2 The Institute of Energy & Sustainable Development, De Montfort University, Leicester,
Great Britain
3 FBTA, University of Karlsruhe, Karlsruhe, Germany
Contact person: agnieszka.psikuta@empa.ch
INTRODUCTION
The number of thermal manikins and their use in research have increased over the past 60
years (Holmer 2004; Wyon 1989). Additionally these manikins have continually advanced
either by improved precision (Richards and McCullough 2004), or by reduced costs (Fan and
Chen 2002). However, still their limitation is their inability to simulate adequately the local
and dynamic thermal behaviour of the human being. A mathematical model of the human
thermoregulatory system incorporated into the system control can provide the local
physiological parameters in real time. Ideally such a device should be able to simulate human
thermal behaviour and comfort perception over a wide range of environmental and personal
conditions whereby the computer model provides the physiological intelligence and the
hardware measures the required calorimetric states relevant to the human heat exchange with
the actual environment.
This paper introduces a single-sector thermophysiological human simulator consisting of the
sweating thermal cylinder Torso (Zimmerli and Weder 1996) coupled with extensively
validated iesd-Fiala model of human physiology and thermal comfort (Fiala et al. 2001),
which aims at mimicking human thermal behaviour with a good accuracy of prediction. This
simulator is designed for a broad range of applications including tests of sleeping bags and
clothing over a wide range of climatic conditions.
METHODS
The iesd-Fiala multi-node model (Fiala et al. 1999), which provides the physiological
variables into the system, is able to simulate human thermal responses under both steady-state
and transient conditions including the thermal history prior to an exposure. The model also
includes a physiological thermal comfort model (Fiala et al. 2003). To measure the
environmental heat exchange the sweating Torso was used, which is at present a widely
employed device for clothing research and testing. The entire device consists of a multilayered
cylinder and two heated aluminium guards, which prevent lateral heat fluxes.
Temperature sensors embedded within the Torso’s layers allow precise measurement of the
heat flux and separately controlled sweating outlets together with the textile ‘skin’ distribute
the sweated liquid.
The coupling method was based on iterative exchange of the mean skin temperature and the
mean sweat rate from the physiological model and the heat flux from the cylinder surface,
which represents the mean human heat flux exchanged with the environment (including
clothing, air and surrounding surfaces). The other physiological parameters such as core
temperature, skin blood flow, heart rate, etc. are also included in the output files. Since the
Torso is a single sector device, the feedback heat flux is applied to all body parts in the
physiological model resulting in the approximation of the true physiological state of the
person.
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