A study of adaptive thermal comfort in a well-controlled climate chamber

• The discrepancy between the PMV and AMV in a well-controlled environment was observed.
• People's long-term living experience in the hot-humid climate accustoms thermal sensation to warm.
• Habituations neutralises thermal sensation due to moderated thermal sensibility of the skin.
• A revised PMVa are proposed as PMVa = 0.22PMV2 + 0.45PMV − 0.1.
• PMVa contributes to the thermal engineering solutions in terms of energy efficiency of an air-conditioning system.

This paper aims to critically examine the application of Predicted Mean Vote (PMV) in an air-conditioned environment in the hot-humid climate region. Experimental studies have been conducted in a climate chamber in Chongqing, China, from 2008 to 2010. A total of 440 thermal responses from participants were obtained. Data analysis reveals that the PMV overestimates occupants' mean thermal sensation in the warm environment (PMV > 0) with a mean bias of 0.296 in accordance with the ASHRAE thermal sensation scales. The Bland–Altman method has been applied to assess the agreement of the PMV and Actual Mean Vote (AMV) and reveals a lack of agreement between them. It is identified that habituation due to the past thermal experience of a long-term living in a specific region could stimulate psychological adaptation. The psychological adaptation can neutralize occupants’ actual thermal sensation by moderating the thermal sensibility of the skin. A thermal sensation empirical model and a PMV-revised index are introduced for air-conditioned indoor environments in hot-humid regions. As a result of habituation, the upper limit effective thermal comfort temperature SET* can be increased by 1.6 °C in a warm season based on the existing international standard. As a result, a great potential for energy saving from the air-conditioning system in summer could be achieved.