An experimental study investigating differences in acclimatization capacity and thermal preference between university students and older workers

¹ Industrial Engineering Department (DIN), University of Bologna, Bologna, Italy
² International Centre for Indoor Environment and Energy, Department of Environmental and Resource Engineering, Technical University of Denmark (DTU), Copenhagen, Denmark

^* Corresponding author: alice.caporale2@unibo.it

Abstract

This experimental study aims to test thermal response and the ability to acclimatize during thermal discomfort conditions of different age groups. Experiments were conducted in late summer with thirteen participants, including university students and older workers, exposed in a climate chamber to a temperature increasing from 22°C to 28°C and decreasing from 22°C to 16°C, at a rate of 3.5K/h. Participants adjusted their clothing to stay thermally neutral at 22°C. After that, they were not allowed to change clothing during temperature ramps. Subjects rated their thermal comfort, preference, and acceptability during increasing and decreasing temperature ramps. Skin temperature was measured in two points to monitor the processes of vasoconstriction. Older workers showed higher vasoconstriction in both ramps due to more rapid and more significant cooling of extremities. However, older workers showed a higher tolerance for thermal discomfort conditions during the cold ramp, suggesting that they might physically suffer more from thermal discomfort but be less aware of it. During the hot ramp, older workers showed greater variability in psychological response, although comparable mean values suggest that thermal neutrality might remain similar with increasing age. For this reason, the percentage of dissatisfied among older workers could be different despite similar neutral temperatures. The results highlight the need to extend the study with comparable experiments to collect further data on older workers' acclimatization capacity and thermal preferences.