Local body cooling to improve sleep quality and thermal comfort in a hot environment

The effects of local body cooling on thermal comfort and sleep quality in a hot environment were investigated in an experiment with 16 male subjects. Sleep quality was evaluated subjectively, using questionnaires completed in the morning, and objectively, by analysis of electroencephalogram (EEG) signals that were continuously monitored during the sleeping period. Compared with no cooling, the largest improvement in thermal comfort and sleep quality was observed when the back and head (neck) were both cooled at a room temperature of 32°C. Back cooling alone also improved thermal comfort and sleep quality, although the effects were less than when cooling both back and head (neck). Mean sleep efficiency was improved from 84.6% in the no cooling condition to 95.3% and 92.8%, respectively, in these conditions, indicating good sleep quality. Head (neck) cooling alone slightly improved thermal comfort and subjective sleep quality and increased Stage N3 sleep, but did not otherwise improve sleep quality. The results show that local cooling applied to large body sections (back and head) could effectively maintain good sleep and improve thermal comfort in a hot environment.     

上海地区村镇住宅热环境与热舒适度研究

利用现场实测方法,对上海一典型村庄进行了夏季及冬季住宅热环境以及居民热舒适性现场实测及调研,研究了上海地区农村住宅热环境及室内热舒适度问题。依据问卷调研结果得到了夏季、冬季农村居民对于住宅环境的可接受温度范围、热中性温度以及期望温度,同时研究了热舒适度的影响因素,可为上海地区村镇住宅节能计算、热舒适环境与绿色生态住宅的设计提供必要的理论依据。     

Evaluation of coupled outdoor and indoor thermal comfort environment and anthropogenic heat

With rapid urbanization, big cities in the south of China are progressively falling short of sustaining outdoor thermal comfort. In this paper, a thermal comfort and energy evaluation model is derived from revisions of previous study, to simulate and predict the interaction of coupled urban building-site climate and then the thermal comfort. The methodology of principal calculations is demonstrated first, then a hypothetical district of office buildings in Shanghai is selected. Dynamic on-site climate parameters, anthropogenic heat and indoor/outdoor SET* values, etc., are simulated and evaluated. The results show the variation of outdoor SET* values influenced by factors including canopy height, building coverage and air-conditioning set-point temperature.     

气流运动及其与热舒适关系研究的进展与评述

指出气流组织的研究对空调节能和保证人体舒适感有着重要的意义,综述了气流运动与热舒适关系及房间气流紊流特征的研究进展,评价了已有的研究成果,对该研究的发展提出了看法。     

Dynamic evaluation of thermal comfort environment of air-conditioned buildings

In this paper, based upon Fanger's thermal comfort concept, several concepts, which utilize computing results obtained from the large eddy simulation (LES), are put forward, such as thermal comfort index based on time-averaged parameters, instantaneous thermal index, time-averaged thermal comfort index and time-averaged thermal comfort index along walking routes. Also their discrepancies and calculation methods are discussed in the paper. Apart from these, we have calculated PD value as an example, whose results indicate that the distributions of four indices are obviously different. Therefore, it is suggested to distinguish different cases and select correspondingly thermal comfort evaluation indices while considering the question of thermal comfort.     

非空调环境下性别与热舒适的关系

对长沙某高校的600多名学生进行了为期一年的现场问卷调查,对有关空气参数进行了测量。统计分析结果表明,女性的耐寒能力比男性差;预期平均评价PMV指标对男女热感觉的预测效果较差;男女对湿感觉的评价无较大差异,只在温度较低时,女性比男性觉得更潮湿;女性的吹风感比男性强;热舒适评价不仅受热、湿感觉影响,还受其他环境因素及心理因素的影响。     

排风口在辐射空调中对于室内热舒适性的影响

以气流组织为研究对象,结合实际工程对有排风口和无排风口的辐射空调系统进行了测试比较,从室内热舒适角度考虑,得出了加设排风口对室内气流温度场和速度场是有影响的。     

关于热感觉和热舒适与热适应性的讨论

系统地论述了人体热舒适研究的发展过程,讨论了热感觉、热舒适及热适应的定义,并分析了热感觉与热舒适的差异及与热适应性的关系,得出了人们对同一热环境有不同的热感觉及热舒适性,主要是由于人体的适应性产生的。     

A comparative analysis of urban and rural residential thermal comfort under natural ventilation environment

The paper presents a field study of occupants’ thermal comfort and residential thermal environment conducted in an urban and a rural area in Hunan province, which is located in central southern China. The study was performed during the cold winter 2006. Twenty-eight naturally ventilated urban residences and 30 also naturally ventilated rural residences were investigated. A comparative analysis was performed on results from urban and rural residences. The mean thermal sensation vote of rural residences is approximately 0.4 higher than that of urban residences at the same operative temperature. Thermal sensation votes calculated by Fanger’s PMV model did not agree with these obtained directly from the questionnaire data. The neutral operative temperature of urban and rural residences is 14.0 and 11.5 °C, respectively. Percentage of acceptable votes of rural occupants is higher than that of urban occupants at the same operative temperature. It suggests that rural occupants may have higher cold tolerance than urban occupants for their physiological acclimatization, or have relative lower thermal expectation than urban occupants because of few air-conditioners used in the rural area. The research will be instrumental to researchers to formulate thermal standards for naturally ventilated buildings in rural areas.     

重庆自然通风热舒适模型的建立及热环境评价

在分析国内外自然通风热舒适研究的基础上,结合重庆地区潮湿的气候特点,对现有自然通风热舒适评价模型进行了湿度修正.采用电子温湿度记录仪对重庆地区村镇典型住宅的室内外热湿参数进行了全年监测,并利用该模型对村镇住宅的室内热环境进行了评价.分析表明,村镇住宅室内和室外相对湿度高于70％的时间分别占全年总时间的95.4％和87.2％,室内温度高于28℃且相对湿度高于70％的时间达1 196 h;全年舒适时间为3 838 h,占全年总时间的43.8％;现有评价模型与修正模型的舒适时间相差405 h,其中空调季相差342h,且温度越高,相对湿度对热舒适的影响越大,说明在温度较高时应考虑相对湿度对热舒适的影响,但修正模型的可靠性还需进一步验证.     

热湿工况下工位辐射空调的热舒适实验研究

为研究热湿工况下使用工位辐射空调的人体热舒适情况,在人工环境实验室内,通过改变环境背景温度来影响人体的热感觉,并采用热感觉投票(TSV)作为评价标准,重点研究了人体头部、躯干、上肢、下肢以及整体热感觉情况。实验结果表明,尽管背景环境参数超出舒适范围,但使用工位辐射空调能维持受试者的舒适状态,即背景温度稳定在28℃时,平均整体热感觉投票值低于+0.2;背景温度为30℃时,受试者热感觉仍能满足ASHRAE规范中规定的80%可接受范围要求。     

现场研究中热舒适指标的选取问题

对热舒适现场研究结果进行了总结，并对热舒适指标的选取、有效温度的计算、热感觉的表述方式等问题进行了讨论分析。认为当相对湿度在热舒适范围内时，采用有效温度作为热舒适指标并采用平均热感觉值，能更好地预测人体热感觉。     

昆明地区夏季居住建筑室内热环境测试及热舒适调查

对昆明市200户住宅夏季室内热环境参数进行了实测,并进行了现场问卷调查。分析了室内温度、相对湿度、风速、人员服装热阻的分布频率,统计得出了昆明地区住宅夏季室内热环境及人体热舒适的基本情况,并分析了室内热环境改善措施。调查发现,昆明市居民夏季普遍通过开窗进行自然通风以降低室内温度,在非空调条件下约有90%的居民的热感觉在舒适范围内。     

Pilot study of the effects of ventilation and ventilation noise on sleep quality in the young and elderly

Three conditions were established to investigate the effects of ventilation and related ventilation noise on sleep quality: No mechanical ventilation/low noise (A); Mechanical ventilation /low noise (B); Mechanical ventilation/high noise (C). The interventions were achieved by idling a mechanical ventilation system or operating it in two different modes. Nine young people and nine older people were all exposed to each of the three conditions for a whole night's sleep, but data from only 15 subjects were analyzed as three young subjects apparently slept with open windows in condition A. Sleep quality was measured objectively with polysomnography (PSG), which monitored signals of electroencephalogram (EEG), bilateral electrooculogram (EOG), and chin electromyogram (EMG) continuously during the sleeping period. Saliva samples were collected before sleep at night and after waking in the morning, and the concentrations of cortisol and lysozyme in them were determined. Without mechanical ventilation, the indoor CO₂ level averaged about 1400 ppm during the night. Operating the mechanical ventilation decreased the indoor CO₂ to below 1000 ppm, which improved objectively measured sleep quality: wake time after sleep onset (WASO) decreased on average by 15 min (p < 0.05) and sleep efficiency (SE) increased on average by about 4% (p < 0.05). Increased ventilation noise level (50.8dB(A) vs. 34.7dB(A); 54.9dB(C) vs. 48dB(C)) did not significantly change SE or WASO but did change the duration of sleep stages: It decreased the duration of deep sleep by 11min (p < 0.05) and REM sleep by 17 min (p < 0.01) and increased the duration of light sleep by 17 min (p < 0.05). The ventilation noise significantly increased the concentration of lysozyme in the elderly (p < 0.05) although no significant effects on cortisol could be shown. These results confirm that a low ventilation rate has negative effects on sleep quality and that ventilation noise at or above 50dB(A) may disrupt sleep.     

厦门高校教室冬季热环境测试及热舒适预测

为考察冬季非空调环境下人体热感觉,对厦门某高校教室的热舒适度进行了现场测试.在测量室内外热舒适参数的同时,通过问卷调查得到了人体热反应样本.分析样本得出厦门高校教室冬季非空调工况下人体热中性温度和热期望温度分别为19.3和19.4℃.综合考虑温度、相对湿度、平均辐射温度、风速及服装热阻对坐姿轻度活动状态人体的热舒适影响,使用MATLAB软件进行非线性回归,得到非空调工况下热舒适预测方程.该预测方程与实测得到的人体热舒适投票两者结果有较高相关度,同时较大程度上反映了冬季非空调环境下人体热感觉的变异.     

Field study on occupants’ thermal comfort and residential thermal environment in a hot-humid climate of China

This paper discusses thermal comfort inside residences of three cities in the hot-humid climate of central southern China. Only a few thermal comfort studies have been performed in hot-humid climates and none in Central Southern China. Field sampling took place in the summers of 2003 and 2004 by obtaining 110 responses to a survey questionnaire and measuring environmental comfort variables in three rooms in each of 26 residences. The objectives are to measure and characterize occupant thermal perceptions in residences, compare observed and predicted percent of dissatisfied and discern differences between this study and similar studies performed in different climate zones. Average clothing insulation for seated subjects was 0.54 clo with 0.15 clo of chairs. Only 48.2% of the measured variables are within the ASHRAE Standard 55-1992 summer comfort zone, but approximately 87.3% of the occupants perceived their thermal conditions acceptable, for subjects adapt to prevailing conditions. The operative temperature denoting the thermal environment accepted by 90% of occupants is 22.0–25.9°. In the ASHRAE seven-point sensation scale, thermal neutral temperature occurs at 28.6°. Preferred temperature, mean temperature requested by respondents, is 22.8°. Results of this study can be used to design low energy consumption systems for occupant thermal comfort in central southern China.     

Impact of dynamic airflow on human thermal response

Airflow fluctuation is an important factor affecting indoor thermal environments and human thermal response. In this study, dynamic airflows with different fluctuation characteristics were generated by a dynamic air supply terminal. The influence of three different kinds of airflows, constant airflow, simulated natural airflow and sinusoidal airflow, on thermal comfort was studied. Subjective experiments indicated that a dynamic airflow can cause a stronger cold sensation, and that air movement with 1/f fluctuations similar to natural wind is more acceptable than other dynamic airflows in warm environments. Moreover, the impact of draughts in dynamic airflows on human thermal response is different in neutral-warm (30 degrees C) and cool-neutral (26 degrees C) thermal environments. PRACTICAL IMPLICATIONS: By means of a dynamic air supply terminal it is possible to generate artificial airflows that simulate natural wind indoors. This kind of airflow with higher velocity is more comfortable and causes less draught sensation than the constant airflows supplied by conventional fans. While the cooling effect of this airflow is utilized in the built environment, the design temperature of air-conditioning system can be increased and the amount of energy consumption can be reduced dramatically.     

关于热舒适模型研究发展的综述

在大量热舒适模型研究的基础上,综述了模型建立的形式、研究的内容、处理问题的方法手段等,总结了目前研究中存在的问题,并对未来热舒适模型的建立和发展提出了展望。     

Evaluation of thermal comfort and indoor air quality in offices

Professor Derek Croome and his colleagues in their CIB Montreal paper present the results of an investigation into the indoor environment of a naturally ventilated office and conclude that data from laboratory tests are insufficient. A field test method is established which allows an investigation to take into account window and door opening patterns and peoples reactions to air temperature, fresh air and movement.     

高原低气压环境对人体热舒适性影响的研究初探

模拟了高原低气压环境,以问卷调查的方式进行了低气压环境下人体热舒适的实验研究,为低气压地区舒适性空调的设计提供了参考.