An Investigation on Occupants’ Metabolic Rate, TSV, and PMV in an Office Building. Study Case: Kanagawa, Japan

Abstract

In actual office activities, there is a possibility that the metabolic rate (MET) value differs from what is set in the standards. Therefore, it is necessary to explore how the actual metabolic rate of office occupants relates to their Thermal Sensation Vote (TSV) and Predicted Mean Vote (PMV). This study investigates the relationship between the actual metabolic rate, the thermal sensation vote (TSV), and the predicted mean vote (PMV) of occupants in an office building. The method of this study is to collect indoor thermal environment data, physiological data, and the subjective responses of building occupants. The study used Silmee Pro W-22 wearable devices to collect the physiological data of building occupants, such as energy expenditure, skin temperature, and heart rate. The subjects of this study were office workers in an office building in Kanagawa, Japan. The investigation was conducted in the transition from winter to spring season (February 28th–March 30th, 2023). The actual office activities varied from the static mode, such as sitting, resting, writing, conversation, and typing, to the dynamic mode, such as walking. The study found significant variations in the metabolic rate of office activities, with the actual metabolic rate being 15% lower than the standard. The regression and correlation analysis showed that the PMV calculation based on the ASHRAE-55 standard significantly correlated to the TSV. In contrast, the PMV calculation based on the actual metabolic rate did not significantly correlate to TSV. The actual metabolic rate may not accurately predict the PMV.