The effect of temperature and air velocity change on human sensation

This report is a part of a study to search whether comfort conditions can be attained by localairflow. In the present experiment, local airflow was directed to two locations of subjectsbody and its effect was examined on which location percepts the airflow more strongly,responds physiologically more sensitively and feels more comfortable. The laboratory airtemperature was set in a range of 26-28C. This experiment was held in summer seasons atToyohashi, Japan. Fifty-four male and female subjects were exposed to airflows of differenttemperatures or velocities directed to the back of the neck and the left ankle. The nozzles ofthe airflow were located at a distance of 0.4 m from the subject surfaces. In one of theexperiment, the air velocity was kept at 0.5 m/s and its temperature was changed to havedifferences of -10, -5, 0, +5 and +10C from the laboratory ambient air temperature. In theother experiment, the velocity of the airflow was changed at 0.00, 0.25, 0.50, 0.75 and 1.00m/s, while its temperature was the same as that of the ambient temperature. In the formerexperiment, the temperature was changed from the lower to the upper temperatures or viceversa with an interval of 15 min. In the latter experiment, the velocity was raised or reduced.The subjects judged the effect of the airflow by voting in the questionnaire of semanticdifferential forms.The results indicated that the necks were more sensitive than the ankles for the temperaturechange and air velocity change. The votes showed that the higher temperature airflow wasmore comfortable than the lower temperature airflow at the both locations. The necks feltmore comfortably for the slow airflows, while the ankles were more comfortable at the fastairflows. The percentage of dissatisfied at the necks were smaller than the ankles.