The response of human thermal sensation and its prediction to temperature step-change (cool-neutral-cool).

Xiuyuan Du,Zhichao Huang,Jianke Liao,Dong Yang,Hong Liu,Wei Yu,Kechao Xia,Baizhan Li,David D Mckemy

doi:10.1371/journal.pone.0104320

Abstract

This paper reports on studies of the effect of temperature step-change (between a cool and a neutral environment) on human thermal sensation and skin temperature. Experiments with three temperature conditions were carried out in a climate chamber during the period in winter. Twelve subjects participated in the experiments simulating moving inside and outside of rooms or cabins with air conditioning. Skin temperatures and thermal sensation were recorded. Results showed overshoot and asymmetry of TSV due to the step-change. Skin temperature changed immediately when subjects entered a new environment. When moving into a neutral environment from cool, dynamic thermal sensation was in the thermal comfort zone and overshoot was not obvious. Air-conditioning in a transitional area should be considered to limit temperature difference to not more than 5°C to decrease the unacceptability of temperature step-change. The linear relationship between thermal sensation and skin temperature or gradient of skin temperature does not apply in a step-change environment. There is a significant linear correlation between TSV and Qloss in the transient environment. Heat loss from the human skin surface can be used to predict dynamic thermal sensation instead of the heat transfer of the whole human body.

Highlights

Thermal comfort research in buildings has primarily focused on steady-state conditions [1,2,3,4,5,6,7,8,9,10], while the thermal environment is often transient and dynamic over time
Physiology response to temperature step has been studied by a number of researchers, and the results show that skin temperature cannot reflect thermal sensation during the transient process, skin temperature correlated best with thermal sensation (r = 0.6) compared with skin moisture and trans-epidermal water loss (TEWL) (r = 0.42–0.54) when the temperature down-step reached 8uC [24,28]
Thermal Sensation Vote (TSV) Fig. 1 shows changes of thermal sensation vote (TSV) over time when subjects had moved between a cool environment and a neutral environment

Summary

Introduction

Thermal comfort research in buildings has primarily focused on steady-state conditions [1,2,3,4,5,6,7,8,9,10], while the thermal environment is often transient and dynamic over time (e.g., when moving indoor from outdoor or moving from indoor to outdoor, and taking a plane, train, boat where air-conditioning is most frequently used to adjust thermal environment to accommodate hot or cold climate). Nagano et al [22] studied the thermal comfort requirements for temperature steps by experiments from hot to neutral, and confirmed that it takes more than 50 min to achieve the steady state. A researcher in German, studied temperature step change (warmneutral) by numerical simulation [27]. Subjects wore a clothing ensemble typical in summer in all these research

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