Indoor Thermal Comfort And Its Influence On Energy And Environmental Characteristics Of Air Conditioning Systems In Nanning

Employing the nationwide and worldwide PMV-PPD index, the indoor thermal comfort in Nanning region is analysed theoretically. Furthermore, the results are compared with the recommended values of the existing standards. Then combined with the climatic conditions of Nanning, the local indoor mean thermal sensation model is established by the method of Standard Effective Temperature (SET*) through the test data and questionnaires. And the results are compared with those of typical cities in other climatic zones. The thermal sensation model in summer Nanning is put forward, namely MTS=0.3719SET*-10.159, and the corresponding neutral temperature of thermal sensation is27.31℃in SET*with a temperature range from24.6to30℃in SET*for satisfaction of80%inhabitants. As well as the local thermal sensation model in winter is MTS=0.216SET*-4.112, and the corresponding neutral temperature of thermal sensation is19℃in SET*with a temperature range from14.4to23.7℃in SET*for satisfaction of80%inhabitants.Taking an office with a split air conditioner in service for example, the influences of load and operation mode of air-conditioning on energy consumption are discussed with the variety of indoor thermal comfort. The results show that air-conditioning could save energy by7.1%as the SET*rising per1℃in summer, and the air-conditioning system will save energy by33%if the operation temperature is set in the upper limit temperature of thermal comfort range rather than the lower limit temperature. The air-conditioning load will increase by6.4%as the SET*increases per1℃in winter.Applying the FLUENT software to simulate the heat rejection jet from the outdoor unit of an air conditioner, the dissertation discusses the impacts of heat rejection on surrounding environment at different indoor and outdoor ambient temperatures under windy and windless conditions. In addition, air entrainment consumed for evacuating heat rejection from air-conditioner, is calculated. Under windy/windless conditions, the effect of outdoor ambient temperature on the temperature field of heat rejection is significant, and the jet velocity decays faster in windy condition than in windless usually. The entrainment discharge is relatively large at higher indoor and outdoor ambient temperatures. At constant indoor/outdoor ambient temperatures, entrainment discharge in wind is smaller than those without wind.According to emergy theory, the impacts of the operation of an air-conditioner on energy and environment are investigated comprehensively. With the increase of outdoor ambient temperature, the transformity (Tr), the net emergy yield ratio (EYR) and the emergy sustainable index (ESI) rise, while the environmental loading ratio (ELR) diminishes. With the rising of indoor return air temperature, the transformity (Tr) decreases and the other indexes don’t change obviously. Furthermore, the effect of different types of pollution on environment can be compared with according to emergy analysis, which finds out the energetic pollution from the operation of an air conditioner consumes more than75394times as many environmental services as the simultaneous material pollution does, and the former is2times than the latter just considering the air conditioner heat rejection.