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|Title: ||Endothermic salts integrated in impermeable suits do not reduce heat strain during exercise|
|Authors: ||Daanen, Hein A.M.|
Wypkema, Aike W.
Cheung, Stephen S.
|Issue Date: ||2013|
|Publisher: ||International Society for Environmental Ergonomics © the authors|
|Citation: ||DAANEN, H.A.M. ... et al., 2013. Endothermic salts integrated in impermeable suits do not reduce heat strain during exercise. IN: Cotter, J.D., Lucas, S.J.E. and Mundel, T. (eds.) Proceedings of the 15th International Conference on Environmental Ergonomics, Queenstown, New Zealand, 11-15 February 2013, pp. 292 - 295.|
|Abstract: ||Wearing impermeable garments during work inherently leads to heat strain, even in cold
environments . Phase change materials (mainly paraffin’s or salt ) may be used as a thermal
buffer (e.g. ) to reduce initial heat stress. Salts can also be used to absorb sweat, which may
enhance the cooling power from the skin.
Recently, specific encapsulated salts utilising KSCN (potassium thiocyanate) have been developed
that consume energy when the KSCN dissolves in water. The heat consumed when the KSCN
(present inside 150 g of capsules containing 60% KSCN salt) dissolves in water is 22410 J (249 J/g *
60% * 150 g). When this solving takes place over a period of 30 minutes, the average power
transfer is 12 W. One (1) g of KSCN-containing capsules absorbs close to 1 g of moisture. If we
assume that 150 g sweat extra can be evaporated from the skin, this yields an extra cooling power
of 182 W for 30 minutes. However this evaporated water from the skin is subsequently absorbed
by the KSCN in the capsules. During this absorption from the gas phase, the condensation heat is
released to the KSCN salt: about 182 W for 30 minutes. However, we hypothesise that this
condensation heat will be partly transferred to the body and partly to the environment ,
providing a net benefit to the body.
Thus, the total cooling effect due to the salt capsules is composed of two parts:
• The cooling effect of about 12 W due to the heat consumption by the dissolving of the salts in
• The cooling effect of maximal 182 W, which equals the difference between the evaporative
heat and the condensation heat. The latter is generated in the salt capsules that transfer part
of the heat to the environment.
The overall cooling effect should therefore be in between 12 W and 194 W.
The purpose of our study was to test the efficacy of a KSCN-based absorbing salt as a PCM for use
within impermeable protective clothing. We tested the PCM during 20 min of moderate exercise
in a hot (35°C, 40% relative humidity) environment, and hypothesized that thermal strain would be
lower in the PCM compared to the non-PCM condition.|
|Description: ||This is a conference paper. The Environmental Ergonomics website is at: http://www.environmental-ergonomics.org/|
|Appears in Collections:||Conference Papers and Presentations (Design School)|
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