DEVELOPMENT OF A TEMPERATURE CONTROL PROCEDURE FOR A ROOM AIR-CONDITIONER USING THE CONCEPT OF JUST NOTICEABLE DIFFERENCE (JND) IN THERMAL SENSATION

Temperature control for an air-conditioner is an important design vari able. Ergonomic studies on the thermal sensation in a normal room temp erature are relatively few while many studies are available for the th ermal sensations in extreme warm/cold conditions. The objective of thi s study is to find out factors which affect the cutaneous thermal sens ations and so to propose a new cooling control procedure for an air-co nditioner using JND (just noticeable difference) values of cutaneous t hermal sensation. An experiment to find out JND values of cool and war m thermal sensation was conducted using 13 subjects. Skin temperature, corresponding room temperature and temperature change rate were measu red using 297 thermocouples uniformly distributed in a thermo-proof ro om. Subjective ratings on thermal sensation and thermal comfort were a lso evaluated. JND values of cutaneous thermal sensation corresponding to the skin, room temperature and temperature change rate were in the range of 0.09-0.80 degrees C. Based on the result of the experiment, a new cooling procedure which lowers the temperature rapidly above the JND values of cool thermal sensation and maintains temperature below the JND values of warm thermal sensation is proposed. (C) 1998 Elsevie r Science B.V. All rights reserved.