“COOL BIZ,” a campaign that encourages air conditioner temperatures to be set at 28˚C and employees to dress accordingly, has been embraced at Japanese business offices in recent years as part of an effort to reduce greenhouse gases. However, offices that actually implement COOL BIZ have reported high employee dissatisfaction with the thermal environment. In this light, it is important that offices with preset air conditioner temperatures ensure comfortable indoor environments for employees, while continuing to save energy. As one of these measures, research has been conducted on air conditioning systems that combine a membrane radiant cooling system, which uses cold air, and a spot air conditioning system, in which the air current can be individually adjusted.

The purpose of our research is to evaluate the comfort level and intellectual productivity provided by personal air conditioning systems, which allow for individual adjustments of the air current. Specifically, we carried out an actual measurement study at offices that installed and are actually operating this air conditioning system, by setting different airflow conditions (adjustable and not adjustable). The results found that employees’ satisfaction with the thermal environment was significantly higher and their comfort level increased when the airflow of personal air conditioning systems was adjustable. The study showed that spot air conditioning systems, which allow for individual adjustments of the air current, have potential for improving the comfort level of employees.

At the above offices where measurements were taken, when the indoor air conditioning systems operated on a rotating basis, the eco-friendliness of the systems improved without undermining the comfort level. These measurements demonstrated that the comfort level of employees at offices with spot air conditioning systems could potentially further improve by giving consideration to the operating method of the air conditioning system and the air temperature setting.

The study demonstrated that the spot air conditioning system’s ability to individually adjust the air current could potentially impact the thermal comfort of employees.

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