Influence Of Air Conditioning Form And Personal Comfort System On Human Thermal Comfort

Thermal environment evaluation standards are usually formulated to meet the requirements of human comfort.Thermal comfort is closely related to physical and mental health,work efficiency and building energy consumption.But the actual indoor environment is affected by solar radiation,cold window effect,different forms of air conditioning and other factors,so the uniformity can not be guaranteed.Therefore,it is of great significance to correctly evaluate thermal environment.Previous studies have focused on the asymmetric radiation environment caused by a single factor,lacking comprehensive consideration of outdoor radiation and air-conditioning form factors,and there are few studies on people taking different adjustment measures to improve their thermal comfort in this environment.Therefore,this study focuses on the thermal comfort characteristics of the human body under the asymmetric radiation environment considering multiple factors,and the influence of different adjustment measures on the thermal comfort of the human body is analyzed.Through the experimental study of occupants’ physiological parameters(skin temperature,blood oxygen saturation,pulse rate)and subjective responses(local and global thermal sensation,local and global thermal comfort,etc.)in the asymmetric radiation environment formed by radiation and convective heat transfer in winter and summer,the change rules of human thermal comfort characteristics in this environment were obtained.On this basis,this study adopted the method of using Personal Comfort System(PCS)and adjusting air conditioning temperature to meet human thermal comfort needs,and established subjective evaluation model and energy consumption behavior model under corresponding working conditions.The results showed that:In terms of the thermal comfort characteristics of human body under different forms of air conditioning,this study found that in asymmetric radiation environment in winter,compared with convection air conditioning,radiant floor had the best improvement effect on the thermal sensation and thermal comfort of calf and foot,and the overall thermal comfort was the best.The radiant ceiling had the best effect on improving thermal sensation and thermal comfort of forearm and back of hand,and the overall thermal sensation voting value was the highest.Radiant ceiling had the highest acceptable proportion to the environment,which was 2% higher than convection air conditioning.In asymmetric radiation environment in summer,compared with convection air conditioning,radiant ceiling had the best effect on improving the thermal sensation of chest and shoulder blade,improving the overall thermal sensation and thermal comfort,and reducing the unacceptable proportion of personnel to the environment by 5%.In terms of the influence of PCS on local and overall thermal sensation and thermal comfort of human body,heated seats are used to directly heat the torso and its vicinity in winter environment,and the most significant thermal sensation improvement is found in shoulder blade(convection),abdomen(radiant floor)and thigh(radiant ceiling),among which PCS combined with radiant floor has the most significant improvement in the acceptable proportion of environment(8%).The most significant improvement in thermal sensation after using fan in summer was in the forehead(convection)and upper arm(radiation ceiling).When PCS was combined with radiant ceiling,the acceptability rate was the highest(97%).In addition,PCS has certain energy saving potential.Under the condition of adjustable environment in summer,the indoor temperature range can be extended by adding PCS,and the corresponding indoor temperature increases by 0.5℃(convection)and 0.6℃(radiant ceiling)respectively when the human body no longer needs to change temperature.Using PCS in different air conditioning forms can save system energy consumption by1.2%(convection air conditioning)and 3.6%(radiant ceiling).On this basis,this study established the local-overall thermal sensation and thermal comfort evaluation model under asymmetric radiation environment,exploring various factors under the influence of the change of the thermal parameters of the overall features,and set up personnel variable temperature demand and subjective reaction model,it was found that the correlation model between thermal sensation and human temperature demand is most suitable for predicting the change of human energy use behavior.When the thermal sensation of human went up or down by 1 unit,the change of human temperature demand is 0.4℃～0.6℃.