Evaporative cooling and heat transfer in functional underwear

Abstract

Purpose

The purpose of this investigation is to measure seven different underwears on a sweating torso with differing relative air humidity (30, 50, 80 and 95 per cent RH) and at a fixed ambient temperature of 30°C to determine the influence of the water vapour partial pressure of the environment on the moisture transport properties of various materials.

Design/methodology/approach

All measurements in this investigation were accomplished with the authors' sweating torso which simulates the thermal‐ and humidity release of the human body. Four different sweating rates (50, 75, 100 and 150 g/h*torso) were selected for this investigation.

Findings

It was established that the partial pressure difference did not correlate directly with the evaporative cooling. In general, higher evaporation rates were observed in the dry climate conditions. However, with low‐sweat rates, the highest relative humidity (95 per cent) generally resulted in greater evaporative cooling than the lowest surrounding humidity conditions (30 per cent). In this investigation, a blended fabric made of PES/Vinal exhibited the most efficient evaporative cooling for all the sweat rates, as well as for the four relative humidity conditions chosen.

Research limitations/implications

All received results are based on a surrounding temperature of 30°C (summer climate), for other temperatures the results may be different.

Originality/value

The investigation shows that both the relative humidity and the sweat rate have a major influence on the heat loss.

Citation

Weder, M., Rossi, R.M., Chaigneau, C. and Tillmann, B. (2008), "Evaporative cooling and heat transfer in functional underwear", International Journal of Clothing Science and Technology, Vol. 20 No. 2, pp. 68-78. https://doi.org/10.1108/09556220810850450