STUDY ON DIFFERENT OFFICE COOLING SYSTEMS ON WORKERS BY SUBJECT EXPERIMENT (PART 1): EFFECTS OF INDOOR ENVIRONMENT DIFFERENCE DUE TO OFFICE COOLING SYSTEMS ON SKIN TEMPERATURE, PSYCHOLOGICAL QUANTITY, AND WORKPLACE PRODUCTIVITY

Increasing the workplace productivity of workers has great economic value and is essential for achieving a sustainable society and economic progress. One way to increase workplace productivity is to improve the work environment, which is important because of its strong influence on workers. The work environment can be improved by using air conditioning to change the thermal environment. In Japan, radiant air-conditioning has received attention as a means to realize energy-saving buildings. However, the difference between the effects of radiant air-conditioning vs. convective air-conditioning on the human body is not clear. Therefore, in this study, we examined these effects on the physiology, psychology, and workplace productivity of workers. In February 2019, we conducted a 5-day experiment with 24 university students (12 males, 12 females). Rooms simulating office conditions were equipped with either a radiant or convection unified air-conditioning system (unified SET*, 27.2°C). In the rooms, the students simulated work such as typing, performing calculations, and creating mind maps between 9:00 and 17:00, changing rooms each day. Physiological measurements such as skin temperature were taken to evaluate stress levels, and a questionnaire was completed by the students to determine perceived comfort. Workplace productivity was evaluated based on the results of the simulated work and questionnaires. The following findings were obtained by this experiment. 1. The skin temperature difference between hands and face (hand-face) was significantly greater in convection air conditioning than in radiant air conditioning for both male and female. It was confirmed that the decrease in the skin surface temperature of the hand with respect to the face had a correlation with psychological quantities such as a decrease in thermal environment satisfaction, a decrease in air flow comfort, and an increase in subjective symptoms. 2. Thermal environment satisfaction was significantly improved in male during convection air conditioning and in female during radiant air conditioning. 3. Thermal environment satisfaction had the strongest correlation with airflow velocity. Focusing on the correlation between thermal environment satisfaction and air velocity during convection air conditioning, positive correlations were found for male and negative correlations for female, confirming different trends for male and female. 4. Focusing on airflow speed and airflow comfort, male tended