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- Zhao, Mengmeng, et al.
(author)
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A Study on Local Cooling of Garments with Ventilation Fans and Openings Placed at Different Torso Sites
- 2013
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In: International Journal of Industrial Ergonomics. - : Elsevier BV. - 0169-8141. ; 43:3, s. 232-237
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Journal article (peer-reviewed)abstract
- Abstract in UndeterminedThe aim of the study was to examine the various design features of ventilatedgarments on cooling performance. Five jackets with small ventilation units andclosable openings were designed. The ventilation units with a flow rate of 12 l/s wereplaced at five different torso sites. They were examined on a sweating thermalmanikin in four clothing opening conditions in a warm environment(Ta=Tmanikin=34 °C, RH=60 %, Va=0.4 m/s). Total torso cooling was increased by 137to 251 %, and clothing total dynamic evaporative resistance was decreased by 43 to69 %. Neither the ventilation location nor the opening design had a significantdifference on total torso cooling. The ventilation location had a significant differenceon localized intra-torso cooling, but not the opening design. When the ventilationunits were placed at the local zone where it was ventilated, that zone underwent thehighest cooling than other local zones. The study indicated that the ventilation unitsshould be placed at the region where it required the most evaporative cooling, e.g.along the spine area and the lower back. The openings could be adjusted (closed oropened) to make comfortable air pressure for the wearers but without makingsignificant difference on the whole torso cooling under this flow rate.
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| 2. |
- Zhao, Mengmeng, et al.
(author)
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The torso cooling of vests incorporated with phase change materials: a sweat evaporation perspective
- 2013
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In: Textile Research Journal. - : SAGE Publications. - 0040-5175 .- 1746-7748. ; 83:4, s. 418-425
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Journal article (peer-reviewed)abstract
- Cooling vests incorporated with phase change materials (PCMs) add extra insulation and restrict sweat evaporation. It is still unclear how much cooling benefit they can provide. The aim of this study was to investigate the torso cooling of the PCM vests in two hot environments: hot humid (HH, 34C, 75% relative humidity (RH)) and hot dry (HD, 34C, 37% RH). A pre-wetted torso fabric skin was used to simulate torso sweating on a thermal manikin. Three cooling vests incorporated with three melting temperatures (Tm) of PCMs were tested (Tm=21C, Tm=24C and Tm=28C). They were worn under a military ensemble (total thermal insulation 1.60 clo; evaporative resistance 0.0516 kPam2/W), respectively. In a HH environment all the three cooling vests provided effective torso cooling; in a HD environment the cooling benefit was negative. In both environmental conditions, the evaporative cooling was greatly restricted by the cooling vests. The study indicated that when wearing the protective clothing with the relatively low evaporative resistance and when sweat production was high, the cooling vests were effective in a HH environment, but not in a HD environment.
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