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  • Gao, Chuansi, et al. (författare)
  • Personal cooling with phase change materials to improve thermal comfort from a heat wave perspective
  • 2012
  • Ingår i: Indoor Air. - Wiley-Blackwell. - 0905-6947. ; 22:6, s. 523-530
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract in Undetermined Abstract The impact of heat waves arising from climate change on human health is predicted to be profound. It is important to be prepared with various preventive measures for such impacts on society. The objective of this study was to investigate whether personal cooling with phase change materials (PCM) could improve thermal comfort in simulated office work at 34°C. Cooling vests with PCM were measured on a thermal manikin before studies on human subjects. Eight male subjects participated in the study in a climatic chamber (T(a) = 34°C, RH = 60%, and ν(a) = 0.4 m/s). Results showed that the cooling effect on the manikin torso was 29.1 W/m(2) in the isothermal condition. The results on the manikin using a constant heating power mode reflect directly the local cooling effect on subjects. The results on the subjects showed that the torso skin temperature decreased by about 2-3°C and remained at 33.3°C. Both whole body and torso thermal sensations were improved. The findings indicate that the personal cooling with PCM can be used as an option to improve thermal comfort for office workers without air conditioning and may be used for vulnerable groups, such as elderly people, when confronted with heat waves. PRACTICAL IMPLICATIONS: Wearable personal cooling integrated with phase change materials has the advantage of cooling human body's micro-environment in contrast to stationary personalized cooling and entire room or building cooling, thus providing greater mobility and helping to save energy. In places where air conditioning is not usually used, this personal cooling method can be used as a preventive measure when confronted with heat waves for office workers, vulnerable populations such as the elderly and disabled people, people with chronic diseases, and for use at home.
  • Kuklane, Kalev, et al. (författare)
  • European manikin standards and models to calculate thermal insulation
  • 2010
  • Ingår i: [Host publication title missing]. - Eighth International Meeting for Manikins and Modeling (8I3M).
  • Konferensbidrag (refereegranskat)abstract
    • ISO 9920 defines three insulation calculation methods: global, parallel and serial. It considers global method a general one that works in any situation, and parallel and serial could be used in specific cases. EN ISO 15831 is the basic manikin testing standard. It gives only two possibilities: parallel and serial. The specific requirements for equations’ use are not set as in ISO 9920, e.g. uniform heat loss or surface temperature. The parallel method is defined similarly to the global in ISO 9920. Thus, the calculation methods’ definitions in the standards differ. EN 342, EN 14058 and EN 13537 for testing cold protective clothing or equipment refer to the methods in EN ISO 15831. Calculation of insulation by any method or using the average insulation of both methods is allowed depending on the test results with reference calibration ensembles. However, several issues need to be considered when using serial method. EN 511 Protective gloves against cold gives its own equation assuming that the whole hand is just one zone. In the case of one zone the serial and the parallel model give the same result. More zones increase the insulation difference between the methods. With uniform surface temperature (required by EN ISO 15831) the parallel method provides the same insulation value with any number of zones while the serial method provides higher value with more zones compared to one zone. EN 342 (cold) and EN 14058 (cool) use the same measuring principles and the same calibration garments. In the case of evenly distributed insulation, the differences in serial and parallel methods are relatively small, and proportional. However, with more insulation layers overlapping in heavy cold protective ensembles the differences increase, and don’t follow the linear relationship any more. The calibration ensembles are selected to represent proper cold protective garments. Thus, if a garment piece does not represent a proper cold protective ensemble (faulty design, manufacturing error) the calibration does not have to be valid. Lately a study on insulation measurements with electrically heated vest was presented. The vest provided an additional 10 W totally to torso region, and turned results from serial method to impossible 83 clo. It may be argued that manikin test is not meant to measure clothing with auxiliary heating. However, what happens if components of an ensemble do employ smart textile technology? A standard should avoid allowing any unrealistic results. EN 13537 Requirements for sleeping bags utilizes the physiological model that has been developed assuming serial values to be correct. It works with properly manufactured sleeping bags. It would be a considerable work to replace the method, although, equally good models are available. Such a major change requires good will and participation from several labs including the ones outside Europe, too.
  • Kuklane, Kalev, et al. (författare)
  • Parallel and serial methods of calculating thermal insulation in European manikin standards
  • 2012
  • Ingår i: International Journal of Occupational Safety and Ergonomics. - Central Institute for Labour Protection, Warszawa, Poland. - 2376-9130. ; 18:2, s. 171-179
  • Tidskriftsartikel (refereegranskat)abstract
    • Standard No. EN 15831:2004 provides 2 methods of calculating insulation: parallel and serial. The parallel method is similar to the global one defined in Standard No. ISO 9920:2007. Standards No. EN 342:2004, EN 14058:2004 and EN 13537:2002 refer to the methods defined in Standard No. EN ISO 15831:2004 for testing cold protective clothing or equipment. However, it is necessary to consider several issues, e.g., referring to measuring human subjects, when using the serial method. With one zone, there is no serial–parallel issue as the results are the same, while more zones increase the difference in insulation value between the methods. If insulation is evenly distributed, differences between the serial and parallel method are relatively small and proportional. However, with more insulation layers overlapping in heavy cold protective ensembles, the serial method produces higher insulation values than the parallel one and human studies. Therefore, the parallel method is recommended for standard testing.
  • Lin, Li-Yen, et al. (författare)
  • A laboratory validation study of comfort and limit temperatures of four sleeping bags defined according to EN 13537 (2002)
  • 2013
  • Ingår i: Applied Ergonomics. - Elsevier. - 1872-9126. ; 44:2, s. 321-326
  • Tidskriftsartikel (refereegranskat)abstract
    • In this study, we validated comfort and limit temperatures of four sleeping bags with different levels of insulation defined according to EN 13537. Six male subjects and four female subjects underwent totally 20 two-hour exposures in four sleeping bags at four intended testing temperatures: 11.2, 3.8, 2.1 and -9.0 degrees C. The subjective perceptions and physiological responses of these subjects were reported and analyzed. It was found that the EN 13537 defined comfort temperature and limit temperature were underestimated for sleeping bags MA3, HAG and MAM. The predictions are so conservative that further revision may be required to meet the requirements of both manufacturers and consumers. In contrast, for the sleeping bag MAO with a low level of insulation, the limit temperature defined by EN 13537 was slightly overestimated. In addition, two individual case studies (-28.0 and -32.0 degrees C) demonstrated that low toe temperatures were widely observed among the male and female subjects, although the mean skin temperatures were almost within the thermoneutrality range (32.0-34.0 degrees C). It seems that the IREQ model (ISO 11079) overestimated both the comfort and limit temperatures of the sleeping bags. Finally, traditional sleeping bags may be required to be re-designed to provide consumers both whole body comfort as well as local thermal comfort at feet/toes or users need to be made aware of the higher need for their insulation. (C) 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.
  • Wang, Faming, et al. (författare)
  • A review of technology of personal heating garments.
  • 2010
  • Ingår i: International Journal of Occupational Safety and Ergonomics. - Central Institute for Labour Protection, Warszawa, Poland. - 2376-9130. ; 16:3, s. 387-404
  • Tidskriftsartikel (refereegranskat)abstract
    • Modern technology makes garments smart, which can help a wearer to manage in specific situations by improving the functionality of the garments. The personal heating garment (PHG) widens the operating temperature range of the garment and improves its protection against the cold. This paper describes several kinds of PHGs worldwide; their advantages and disadvantages are also addressed. Some challenges and suggestions are finally addressed with regard to the development of PHGs.
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