A Case Study In The Hot-humid Area Of China Of Human Thermal Comfort For People Lying At Rest In Environments Cooled By Fans And Air Conditioners

There are high energy consumption and poor health problems due to the reliance on the air conditions to create steady state thermal environments in hot and humid area in China,and the useful effects of the fans in the environment control in residential buildings are neglected.If the fans produce air flow and the air conditions control temperature simultaneously,the indoor thermal environment will be notably improved,and the energy consumption of the air conditions will be greatly reduced because the runtime is shortened and the high temperature set point is raised.Airflow can greatly improve human thermal comfort under high temperature or high humidity conditions and reduce air conditioning energy use.This has been extensively studied in view of the well-known compensation effects of air speed on air temperature and humidity.But the existing research based on sitting in the office environment,for lying at rest or sleeping environments of human body thermal comfort research is less.A human being spends approximately one-third of his/her life in sleep.Lying at rest and sleeping environments have extreme similarities,such as thermal response,human body metabolism rate and so on,lying at rest is the preparatory stage for sleep,so thermal comfort in lying at rest is necessary and important.This thesis is based on Fuzhou which is located in South-eastern China and is a typical city in the hot-humid areas of China.Sixty-one healthy Chinese college students participated in the study.The experimental room was located on the fourth floor of a teaching building at Fuzhou University.The purpose of the study is to conduct experiments on human thermal responses for people lying at rest in various indoor conditions cooled by fans and air conditioners,to determine the acceptable range of air temperature,humidity and air speed for people lying at rest,and to provide references for comfortable sleeping environments in hot-humid areas.The results show that human thermal comfort can be maintained while lying at rest by supplying airflow at air temperatures of 27-30℃ and humidities of 40%-80%for the people in the hot-humid area of China.The air speeds for thermal neutrality were between 0.22 m/s(for 27℃ and 40%-60%RH)and 1.15 m/s(for 30℃ and 60%-80%RH),and the wind speeds for 80%thermal acceptability were between 0.13 m/s and 1.32 m/s.A higher air speed was needed to maintain the same thermal sensation at a higher air temperature or relative humidity.The air speeds for thermal neutrality of people lying at rest in the present study are significantly lower than those of people in sedentary activities in the previous studies due to the lying at rest posture and the lower metabolic rates of the subjects.More than 80%of the subjects felt acceptable with the airflow and humidity conditions for their long-term life in the hot-humid environment and frequent using of fans.The airflow of fans effected human thermal sensation mainly by influencing the skin temperatures of the exposed body parts.The skin temperatures were kept constant at 32.7℃ and 35.1℃ for the exposed and non-exposed body parts respectively when the air speeds for thermal comfort were provided.The findings of the study will be applied to control fans and air conditioners automatically to create a comfortable thermal environment for a short rest and pre-sleep and reduce the energy consumption.