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Heat stress is a common danger for people who work or exercise in hot environments. A Newton manikin was used to evaluate the cooling performance of five forced air ventilation garments (AVGs) with newly designed eyelet sizes and positions, including no eyelets (control), small eyelets at the mid-back, large eyelets at the mid-back, small eyelets at both the mid-back and upper front, large eyelets at both the mid-back and upper front (abbr. CON, B1, B2, FB1, FB2, respectively). The AVGs in fans turned on (Fan-On) and turned off (Fan-Off) were measured in a constant temperature mode (CT, 34 °C, 69% RH, and 0.20 m/s) and a thermoregulatory control mode (TMC, 30 °C, 69% RH, and 0.2 m/s) to simulate human exercising and resting. Air volume between the skin and clothing was also measured using a 3 D laser scanner. FB1 resulted the highest heat loss both in the chest zone (109.2 W/m2) and the stomach zone (77.1 W/m2) in the Fan-On conditions, and it also resulted the lowest torso skin temperature, mean skin temperature and core temperature. The air volume of the eyelet designs in Fan-On was all reduced when compared to that of CON, with FB2 having the greatest reduction by 14.5%. The eyelet designs significantly reduced clothing bulkiness (p < 0.05), but had no significant effect on the torso heat loss (p > 0.05). [ABSTRACT FROM AUTHOR]

Effects of clothing size and air ventilation rate on the cooling performance of three air ventilation jackets (size small, medium and large) were investigated. Two ventilation rates were chosen: low ventilation (12 L/s) and high ventilation (20 L/s). A significant difference in the dry heat loss at the upper body excluding the head and hands (UBody) was noted among the three sizes (p < 0.05). The ventilation rate significantly increased the total UBody heat loss and thereby reduced UBody's apparent evaporative resistance (p < 0.05). Clothing size showed varied impact on the UBody heat loss and the impact varied with air ventilation rates. Air ventilation could greatly reduce predicted core temperatures, mean skin and UBody temperatures in both sizes small and large. In contrast, clothing size had almost no impact on predicted thermophysiological responses in high ventilation. This work may be useful for designing and improving high-performance air ventilation clothing. [ABSTRACT FROM AUTHOR]

In this study, the air layer distribution and evaporative resistances of 39 sets of male Chinese ethnic clothing were investigated using a sweating thermal manikin and the three-dimensional (3D) body scanning technique. Relationships between the evaporative resistance and air layers (i.e., air gap thickness and air volume) were explored. The results demonstrated that the clothing total evaporative resistance increases with the increasing air gap size/air volume, but the rate of increase gradually decreases as the mean air gap size or the total air volume becomes larger. The clothing total evaporative resistance reaches its maximum when the average air gap size and the total air volume are 41.6 mm and 69.9 dm(3), respectively. Similar general trends were also found between local mean air gap size and clothing local evaporative resistance at different body parts. However, different body parts show varied rates of increase and decrease in the local evaporative resistance. The research findings provide a comprehensive database for predicting overall and local human thermal comfort while wearing male Chinese ethnic clothing. [ABSTRACT FROM AUTHOR]

‘Wet’ thermal insulation, defined as the thermal insulation when clothing gets partially or fully wet, is an important physical parameter to quantify clothing thermal comfort. As the water/sweat gradually occupies the intra-yarn and inter-yarn air voids of the clothing material, the clothing intrinsic thermal insulation will be diminished and, hence, contribute to the loss of total insulation. In cold conditions, a loss in total thermal insulation caused by sweating may result in an inadequate thermal insulation to keep thermal balance and eventually leads to the development of hypothermia and cold injuries. Therefore, it is imperative to investigate the effect of clothing fit and moisture content on clothing ‘wet’ insulation. In this study, the ‘wet’ thermal insulation of three two-layer clothing ensembles was determined using a Newton thermal manikin. Four levels of moisture content were added to the underwear: 100, 200, 500 and 700 g. The clothing apparent ‘wet’ thermal insulation under different testing scenarios was calculated and compared. A third-degree polynomial relationship between the reduction in ‘wet’ thermal insulation and the moisture content added to underwear was obtained. Further, it was evident that the clothing fit has a minimal effect on the apparent ‘wet’ thermal insulation. The findings may have important applications in designing and engineering functional cold weather clothing and immersion suits. [ABSTRACT FROM AUTHOR]

This paper addresses selection between two calculation options, i.e heat loss option and mass loss option, for thermal manikin measurements on clothing evaporative resistance conducted in an isothermal condition (Tmanikin = Ta = Tr). Five vocational clothing ensembles with a thermal insulation range of 1.05–2.58 clo were selected and measured on a sweating thermal manikin ‘Tore’. The reasons why the isothermal heat loss method generates a higher evaporative resistance than that of the mass loss method were thoroughly investigated. In addition, an indirect approach was applied to determine the amount of evaporative heat energy taken from the environment. It was found that clothing evaporative resistance values by the heat loss option were 11.2–37.1% greater than those based on the mass loss option. The percentage of evaporative heat loss taken from the environment (He,env) for all test scenarios ranged from 10.9 to 23.8%. The real evaporative cooling efficiency ranged from 0.762 to 0.891, respectively. Furthermore, it is evident that the evaporative heat loss difference introduced by those two options was equal to the heat energy taken from the environment. In order to eliminate the combined effects of dry heat transfer, condensation, and heat pipe on clothing evaporative resistance, it is suggested that manikin measurements on the determination of clothing evaporative resistance should be performed in an isothermal condition. Moreover, the mass loss method should be applied to calculate clothing evaporative resistance. The isothermal heat loss method would appear to overestimate heat stress and thus should be corrected before use. [ABSTRACT FROM AUTHOR]

Abstract: Clothing evaporative resistance is an important input in thermal comfort models. Thermal manikin tests give the most accurate and reliable evaporative resistance values for clothing. The calculation methods of clothing evaporative resistance require the sweating skin surface temperature (i.e., options 1 and 2). However, prevailing calculation methods of clothing evaporative resistance (i.e., options 3 and 4) are based on the controlled nude manikin surface temperature due to the sensory measurement difficulty. In order to overcome the difficulty of attaching temperature sensors to the wet skin surface and to enhance the calculation accuracy on evaporative resistance, we conducted an intensive skin study on a thermal manikin ‘Tore’. The relationship among the nude manikin surface temperature, the total heat loss and the wet skin surface temperature in three ambient conditions was investigated. A universal empirical equation to predict the wet skin surface temperature of a sweating thermal manikin was developed and validated on the manikin dressed in six different clothing ensembles. The skin surface temperature prediction equation in an ambient temperature range between 25.0 and 34.0°C is T sk =34.0–0.0132HL. It is demonstrated that the universal empirical equation is a good alternative to predicting the wet skin surface temperature and facilitates calculating the evaporative resistance of permeable clothing ensembles. Further studies on the validation of the empirical equation on different thermal manikins are needed however. [Copyright &y& Elsevier]

We studied the heating efficiency of an electrically heated vest (EHV), its relationship to the microclimate temperature distribution in a three-layer clothing ensemble, and the effect of an EHV on the clothing's total thermal insulation by both theoretical analysis and thermal manikin measurements. The heat losses at different ambient conditions and heating states were recorded and the heating efficiency of the EHV was calculated. It was found that the EHV can alter the microclimatic temperature distribution of the three-layer clothing ensemble. The EHV can provide an air temperature of 34°C around the manikin's torso skin. The highest temperature on the outside surface of the EHV was around 38°C, which indicates that it is safe for the consumer. The higher the heating temperature, the lower the heating efficiency obtained. This was due to much more heat being lost to the environment, and hence, the heat gain from the EHV was smaller. The heating efficiency decreased from 55.3% at 0°C to 27.4% at −10°C when the heating power was set at 13 W. We suggest adjusting the heating power to 5 W (step 1) at an ambient temperature of 0°C, while at −10°C using 13 W (step 3) to provide the consumer a thermal comfort condition. [ABSTRACT FROM PUBLISHER]

The main aim of this paper is to contribute to finding a good solution to the ethical problem of live plucking. The use of new eco-environmental kapok fibres as a coat filler substitute for traditional duckling down was reported. The physical structures of kapok fibre were studied by scanning electron microscopy (SEM). The thermal and evaporative resistance properties of twelve sets of traditional duckling down coats and kapok coats were measured and compared using a novel sweating thermal manikin called "Walter". The results showed that there are no significant statistical differences in thermal and evaporative resistances among traditional duckling down coats and kapok coats. It was also found that there is the best mix rate of material and air trapped inside, which provides the best thermal resistance for the coat. Finally, we proposed that kapok fibres be used as a coat filling to lower the product price. Most importantly, the use of kapok fibre results in as good thermal and evaporative resistances of a coat as with traditional duckling down. [ABSTRACT FROM AUTHOR]

• A 3D numerical model is developed for air ventilation clothing based on CFD. • Human body model with actual geometry, size and shape is obtained by 3D scanning. • Numerical model is validated against thermal manikin experiments and human trials. • Local heat transfer coefficient with clothing and its cooling power are determined. Building energy demands can be reduced significantly with the use of personal cooling clothing where only the microclimate around body is cooled instead of cooling the entire building or rooms using HVAC systems. In the present study, a three-dimensional numerical model of a virtual thermal manikin wearing an air ventilation cooling clothing with actual dimensions and shape was developed to determine heat transfer between the human body and the environment. The actual geometric model was developed based on data obtained from 3D body scanning experiments. Governing fluid flow and energy equations were solved along with the standard k-ε turbulence model. Experiments were carried out to determine accuracy of the developed numerical model. Validation studies were performed by comparing numerical results with experimental results obtained by conducting both thermal manikin experiments and human trials. Good agreement between the two was found. Fluid flow and temperature distribution in the clothing microclimate, local heat flux and convective heat transfer coefficients at various locations in the human body, the sensible heat transfer between the human body and environment and the effect of fan air flow rate on body cooling performance were also analyzed. Maximum heat transfer or cooling was observed in the lower back segment of the body with convective heat transfer coefficient 38.62 W/m2K. Overall, torso heat transfer was found to be 273.44 W/m2 which corresponds to 154.73 W cooling power and 0.24 cooling efficiency of the air ventilation clothing at 20.0 ± 0.5 °C, 65 ± 5% and 0.4 ± 0.1 m/s. It was noted that the area-weighted average torso heat flux increased as the fan air flow rate increased. [ABSTRACT FROM AUTHOR]