Thermal Sensation Based Humidity Control to Improve Thermal Comfort and Energy Consumption in Non Hot-Dry Climate Zones
Evaporative cooling strategies have been successfully applied in the hot-dry climate zone. In other climate zones, air-or watercooled air conditioners are common strategies. While the latter cooling strategies may do well in providing an acceptable air temperature range, alone they risk unfavorable conditions for other thermal comfort factors. They may result in low indoor humidity levels (below 30％) even in mildly humid outdoor climates or low thermal sensation (TS) values (e.g. 23℃ and 40％ relative humidity has a TS value of-0.9: cold). To address these shortcomings, this study investigated the benefit of actively controlling humidity to improve thermal comfort and energy efficiency in climate zones other than hot-dry. Three eases were experimentally tested in a full scale mock up of an office environment. The first case only controlled air temperature with a target of 23-26℃. The second case controlled both air temperature and humidity, but independent of each other. Target values were 23-26~C and 30-60％ RH. The third case employed an active approach to controlling humidity by adopting a TS value as a control criterion. Using a control logic, the cooling system was turned on when the TS value was over 0.5 and off when under -0.5. On the other hand, the humidifier was turned on when the TS value was under -0.5 and off when over 0.5. The study revealed that air temperature was better controlled in the occupied zone under the first two cases than the TS based method. Over an eight hour period, the first two methods were able to maintain a temperature range of 23-26℃ for 84.2％ and 90.6％ of the time respectively. The TS based method maintained the temperature range for 46.0％ of the time. However, TS levels were best achieved under the TS value control criterion case (89.6％ of test period) followed by the temperature and humidity control case (69.2％). The air temperature only ease performed poorly (37.6％) due to low humidity. Energy consumption was significantly reduced when humidity was actively controlled for thermal comfort. The TS-based ease consumed 802 Wh, while the temperature only ease consumed 5290 Wh and the temperature plus humidity ease consumed 5940 Wh. This study indicated that adoption of an active humidity control system based on TS can provide increased thermal comfort as well as energy savings for summer seasons in climatic zones other than hot-dry.
Thermal comfort Thermal sensation Humidity control
Jin W Moon Jae D Chang
School of Architecture,Design and Planning,University of Kansas,USA
国际会议
The 6th International Symposium on Heating,Ventilating and Air Conditioning(第六届国际暖通空调学术会议)
南京
英文
271-277
2009-11-06（万方平台首次上网日期，不代表论文的发表时间）