空气流动对室内健康体育运动人体热舒适的影响及设计策略研究

Low Energy Thermal Comfort with Air Movement in Sports Facilities

本文通过实验室实验、主观问卷和能耗模拟的方法,研究室内健康体育运动中空气流动对运动状态下人体热舒适的影响及其节能效果,得出以下结论:运动状态下人体对温度和风速均有更大的接受和适应范围;运动强度增加时对风速的需求增加,气流可通过增加人体表面蒸发和对流散热量而补偿环境温度的升高,在保证人体舒适的同时显著节约建筑制冷能耗。基于以上结论探讨了采用空气流动时室内健康体育运动空间热环境设计和改进策略。

With the development of China’s economy and the improvement of people’s living quality, people are paying more and more attention on doing physical exercise regularly. Therefore, the demand for indoor spaces such as sports and fitness centers gets higher recently. Exercising people need lower temperature to maintain comfort because of their higher metabolic rates, making indoor sports facilities energy intensive in warm climates. In absence of comfort standard for sports facilities, it is necessary to find efficient cooling strategies in such spaces to maintain comfortable indoor environment while saving energy. This study aimed to investigate comfort and energy performance of air movement on cooling exercising people in warm temperatures. Twenty subjects (10 men, 10 women) were exposed to four temperatures (20℃, 22℃, 24℃, 26℃, 50% RH) while exercising at 2, 4 and 6 MET on an ergometer for 60 min (20 min for each MET), during which they could control a ceiling fan based on their thermal preference. A separate control condition of 20℃ with no fan (20NF) was also tested. The fan power was monitored to predict the corresponding preferred air speeds (PAP). They were surveyed on their thermal comfort at the end of each MET session. Energy saving potential with air movement were conducted using EnergyPlus. The model building was designed to be a 4 000 m2, single story fitness center. Modifications were made to either meet minimum ventilation requirements and lighting standards. The energy model was tested in five different cities in different climate zones (including Harbin, Beijing, Shanghai, Guangzhou, Kunming) with changing setpoint temperature (SP) from 20℃ to 22℃, 24℃, and 26℃. The current study found that air movement was able to maintain the same level of thermal comfort at warmer temperatures than a control temperature of 20℃ at 2, 4 and MET. This has important implication in sports facilities, for which could be cooled with air movement at higher room setpoint temperatures. The significant energy saving potential should be encouraging for designer to pursue alternative cooling with air movement in sports facilities. The preferred air speeds for each MET and temperatures has important implication for conditioning spaces for different activities in sports facilities. Results showed that human has a greater acceptance and adaptation range for temperature and air speeds during exercise than sedentary state. The comfort could be maintained at warmer temperatures up to 26℃ with air movement compared to 20℃ with no air movement at 2, 4 and 6 MET. When the exercise intensity increases, the demand for air speeds increases. And MET had a significant effect on preferred air speeds especially at 6 MET, for which subject preferred 1.2 m/s even at 20℃. The energy saving potential for all cities by increasing setpoint temperature from 20℃ were 18%~41% at 22℃ SP, 38%~72% 24℃ SP and 61%~86% 26℃ SP for different climates. Air movement can compensate for the increase of the ambient temperature by increasing the surface evaporation and convection heat dissipation of the human body, saving the building cooling energy while ensuring the comfort of the human body. Compared with the front air supply, the uniform air movement at the top is more effective for improving the thermal comfort of the human body during exercise. In conclusion, human thermal comfort could be maintained at warmer temperatures up to 26℃ SP with personal controlled air movement, compared to 20℃ SP with no air movement. People preferred higher air speeds during exercise than sedentary state. By using air movement in sports facilities with elevated SP temperature, significant energy can be saved. Relationships of ambient temperature and preferred air speed at different activity levels were established, which could be used in developing automatic control algorithms for sports facilities.