Field study on occupants’ subjective symptoms attributed to overcooled environments in air-conditioned offices in hot and humid climates of Asia

Yuta Fukawa*, Ryota Murakami, Masayuki Ichinose

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Indoor thermal environments in various offices in hot and humid climate regions of Asia are overcooled by air conditioning (AC) systems. Overcooled environments affect the occupants’ health and lead to excessive energy consumption. This study aims to clarify the association of occupants’ subjective symptoms with indoor thermal environments through field surveys conducted in Thailand, Indonesia, and Singapore. Indoor thermal measurement and thermal comfort surveys, including a questionnaire about thermal sensation and subjective symptoms, were conducted, targeting 599 occupants in 11 offices. The results showed that the mean indoor operative temperatures (Top) for all cities were lower than 24°C. More than half of the occupants wore light clothing ensembles (0.30–0.59 clo). Therefore, 42.6% of the occupants’ calculated predicted mean vote (PMV) was less than −0.5. The correlation between indoor temperatures and the actual percentage of occupants who reported subjective symptoms (APSS) was analyzed. The lower Top and standard new effective temperature (SET*), the more APSS was increased. In each temperature category of below 24.5°C, more than 30% of occupants reported subjective symptoms related to coldness. Therefore, the findings from this study suggest that raising Top higher than 24.5°C is a first step to minimize the harmful effects of the cooling environments on the occupants’ health in this region. As the number of samples in the higher temperature range was insufficient in this study, further experiments in actual offices are necessary to verify the reduction of occupants who report subjective symptoms while raising the setpoint temperature.

Original languageEnglish
Article number107741
JournalBuilding and Environment
Volume195
DOIs
Publication statusPublished - 2021 May 15

Keywords

  • Air conditioning
  • Hot-humid climate
  • Office building
  • Overcooled environment
  • Subjective symptom
  • Thermal comfort

ASJC Scopus subject areas

  • Environmental Engineering
  • Civil and Structural Engineering
  • Geography, Planning and Development
  • Building and Construction

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