Variations of PMV based Thermal Comfort and Cooling/Heating Load according to MET

Abstract

Purpose: Korean government originally established the target of greenhouse gas emission reduction by 30% by the year of 2020, but adjusted the target to 37% reduction by 2030, recently. The efficient indoor environmental control is an essential factor for the achievement of the goal. However, most of the indoor environment control is based on the dry-bulb air temperature, which is one of the most simplified control methods having limitation to truly represent thermal comfort of individual occupants. A variety of factors affect the thermal comfort such as dry-bulb air temperature, humidity, air movement, radiation, clothing insulation and metabolic activity level. Method: In this circumstance, this study investigated the effects of MET (metabolic rate) on thermal load and PMV, which is the thermal comfort index considering all the comfort factors listed above. Four cased were simulated using EnergyPlus: Case1: 0.7 (Sleeping), Case2: 1.0 (Seated, quiet), Case3: 2.0 (Walking), Case4: 2.3 (Fast walking, Dish washing). Result: It turned out that indoor air temperature in MET 0.7 Case can be even 10℃ higher than that in MET 2.3 Case to accomplish the same PMV in the summer period and that MET has dominant effects on heating and cooling load in residential buildings.