Field surveys on indoor environment and thermal comfort in a centralized HVAC office building

The investigated office building is a two-storey building with a floor area of 3404m2. It is located in the Sendai City Japan, where the winter climate can be characterized as long and cold. Due to high densities of occupants and office appliances, it uses centralized airconditioners for cooling even in winter. One third of the workers have moved to another building in January 2009, and the investigations on thermal environment have been carried out before and after this moving out. The results showed that before moving out, indoor air temperature stayed around 24∼28°C during the business hours, even though air-conditioners were set at 25°C for cooling. More than 90% of the occupants complained about the hot and dry environment, and they found difficulty in proceeding to their work efficiently. On the other hand, air-conditioners were set at 23°C for heating after the moving out. Indoor air temperature was about 23∼25°C and the percentages of acceptable voted by the respondents were higher than before.