6
E. Classen
As a link to reality, this heating power equates the heat loss of the skin (identical
with the heat loss of the fabric) due to the evaporation of sweat and can be described
as the ability to lose evaporative heat when wearing this kind of clothing. So, the
higher this heating power, the higher is the physiological cooling effect, that is, the
cooler the fabric is perceived on the skin.
2.3 Wearer Trials
To determine the influence of cooling textiles on human thermoregulation and
temperature perception wear trials with subjects were performed. Test design
followed ethical rules and written informed consent was obtained from all participants.
Five male subjects (28.8 ± 3.2 years, 178.8 ± 7.3 cm, BMI 23.6 ± 1.1) performed
a standardized activity protocol in a climatic chamber (temperature T a = 25 °C,
relative humidity RH a = 50% rh). Subjects were running on a treadmill with different
speeds: 4 and 6 km/h. They were wearing cooling shirts and additional standard
clothing (short pants, socks, shoes). Samples for the cooling shirts were chosen by
the results of the heat release tester. Every subject performed three trials with one
t-shirt. Samples were pre-acclimatized for at least two hours. Trial duration was
120 min with a activity and rest program (0–20 min: sitting on a chair (rest); 20–
60 min walking with a speed of 4 km/h; 61–80 min: sitting on a chair (rest) and
81–120 min walking with a speed of 6 km/h.
T-shirts were made from three different cooling textiles with different cooling
behavior (fabric 1, 2 and 3). To produce the T-shirts of the wearer trials enough
material had to be available; this was only the case of the fabric 1, 2 and 3. All other
investigated materials were ready-made products and could not use in the wearer
trials. For a fit of the T-shirts, the size and shape of the test subjects were determined
with 3D-Scanning to achieve the body data for the sewing of well-fitted T-shirts. To
achieve a high cooling effect the T-shirt must be worn closed to the body of the test
subjects. Objective data of the test subjects (e.g., heart rate, core temperature, skin
temperature and humidity, weight loss) with sensors and data logger and subjective
feedback were recorded during and after the subject trials.
3 Results and Discussion
Figure 2 shows the results of 10 investigated products from the market with the heat
release tester. The samples were put on the WATson measuring head in the dry state.
Sweating was switched on at t = 10 min and performed until a constant heating
power was achieved again (i.e., heat loss in wet state). Then sweating was turned
off (t = 70 min) and the test was performed until the samples were dry again (i.e.,
drying time, the decay of heat loss over time).
E. Classen
As a link to reality, this heating power equates the heat loss of the skin (identical
with the heat loss of the fabric) due to the evaporation of sweat and can be described
as the ability to lose evaporative heat when wearing this kind of clothing. So, the
higher this heating power, the higher is the physiological cooling effect, that is, the
cooler the fabric is perceived on the skin.
2.3 Wearer Trials
To determine the influence of cooling textiles on human thermoregulation and
temperature perception wear trials with subjects were performed. Test design
followed ethical rules and written informed consent was obtained from all participants.
Five male subjects (28.8 ± 3.2 years, 178.8 ± 7.3 cm, BMI 23.6 ± 1.1) performed
a standardized activity protocol in a climatic chamber (temperature T a = 25 °C,
relative humidity RH a = 50% rh). Subjects were running on a treadmill with different
speeds: 4 and 6 km/h. They were wearing cooling shirts and additional standard
clothing (short pants, socks, shoes). Samples for the cooling shirts were chosen by
the results of the heat release tester. Every subject performed three trials with one
t-shirt. Samples were pre-acclimatized for at least two hours. Trial duration was
120 min with a activity and rest program (0–20 min: sitting on a chair (rest); 20–
60 min walking with a speed of 4 km/h; 61–80 min: sitting on a chair (rest) and
81–120 min walking with a speed of 6 km/h.
T-shirts were made from three different cooling textiles with different cooling
behavior (fabric 1, 2 and 3). To produce the T-shirts of the wearer trials enough
material had to be available; this was only the case of the fabric 1, 2 and 3. All other
investigated materials were ready-made products and could not use in the wearer
trials. For a fit of the T-shirts, the size and shape of the test subjects were determined
with 3D-Scanning to achieve the body data for the sewing of well-fitted T-shirts. To
achieve a high cooling effect the T-shirt must be worn closed to the body of the test
subjects. Objective data of the test subjects (e.g., heart rate, core temperature, skin
temperature and humidity, weight loss) with sensors and data logger and subjective
feedback were recorded during and after the subject trials.
3 Results and Discussion
Figure 2 shows the results of 10 investigated products from the market with the heat
release tester. The samples were put on the WATson measuring head in the dry state.
Sweating was switched on at t = 10 min and performed until a constant heating
power was achieved again (i.e., heat loss in wet state). Then sweating was turned
off (t = 70 min) and the test was performed until the samples were dry again (i.e.,
drying time, the decay of heat loss over time).