| People spend one third of their lives on sleeping,and comfortable environment can improve their sleep qualities.Previous studies focused on the effects of high or low temperatures,airflow and temperature changes on sleep,revealed the advantages of airflow and some dynamic changes on improving sleep quality,and indicated the energy saving potentials by temperature fluctuations and heating in the late stage of sleep.The summer is long,hot and humid,and the cooling energy is huge in the hot-humid area of China.Previous studies indicate that local people can adapt to the hot-humid climate well.This paper aimed to study the effects of temperature and air speed combinations and dynamic environments on the sleep quality of people in the hot-humid area,and identify the appropriate environments that improve sleep quality and save energy.The field tests were conducted in 4 comparable dormitories at South China University of Technology in Guangzhou(a typical city in the hot-humid area).Sixteen college students without sleep disorder(PSQI global score≤7),half male and half female,participated in the tests.They wear short-sleeved pajamas and covered with blankets for summer sleep,and the insulation of bedding system was estimated to be 1.46 clo according to.Five test conditions with potentials in improving sleep quality and saving energy were proposed as follows: C1,neutral condition,27 °C,no airflow;C2,"neutral→slightly warm" air speed changing condition,29 °C,0.8 m/s in the former 4h,0.6 m/s in the later 4h;C3,"neutral→slightly warm→neutral" air speed changing condition,the same as C2 except for 0.8 m/s in the last 1h;C4: "neutral→slightly warm" temperature changing condition,27 °C in the former 4h,28.5 °C in the later 4h,no airflow;C5: "Neutral→slightly warm→neutral" temperature changing condition,the same as C4 except for 27 °C in the last 1.5h.The results show that: the neutral environment without airflow was more helpful for sleep onset than that with airflow by showing shorter SOL and more comfort.The "neutral→slightly warm" dynamic thermal environments caused by changing temperature or air speed provided the same sleep quality with the neutral thermal environment during sleeping.The neutral environments with or without airflow and the slight warm environment with airflow were the same for awakening by showing similar refreshment of awakening,comfort and acceptability.The energy consumption was reduced in order of constant temperature condition,temperature changing condition,and air speed changing condition.The sleep quality can be maintained and 97% of energy can be saved by making full use of airflow to create a sleep dynamic thermal environment.It reveals that TSV is shifted toward the cold side in windy conditions and is no significant difference in windless conditions.Contrary to TSV,there is no significant difference in TCV and TAV in windy conditions and there is decline in TCV and TAV in windless conditions.In addition,the results also revealed differences in sleep quality between sexes in different conditions: men were more likely to fall asleep in the neutral environment without airflow than that with airflow by showing shorter SOL and more comfort while women prefered the neutral environment with airflow before sleep.Men reported better sleep quality than women by showing higher score in sleep quality questionnaires and women felt more comfortable in all conditions while men were too warm after they woke up. |
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