Exceedance Degree-Hours: A new method for assessing long-term thermal conditions

Several “discomfort indices” have been proposed and codified into building standards, with several needs usually reported for such indices. They should: express the severity of discomfort in time steps while incorporating all environmental and personal factors; be usable with any comfort model (and thus, a variety of interests, for example, traditional thermal comfort, sleep comfort), among other requirements. The existing indices, however, fall short of meeting all these goals, limiting their usefulness in many situations, such as assessing conditions in mixed-mode buildings, especially when used for building performance simulation and design optimization purposes. Here, a new discomfort index called “Exceedance Degree-Hours” is developed, which accounts for all six main environmental and personal factors. By using an equivalent temperature index, “Exceedance Degree-Hours” can capture variations in discomfort severity between different thermal conditions that other indices cannot. In contrast with other indices, “Exceedance Degree-Hours” can be paired with various comfort definitions from literature, and, importantly, it can be used to assess thermal comfort in mixed-mode buildings, providing a single value as a result. Here, the results of the proposed method are compared to those of existing discomfort indices suggested in standards, and the advantages and limitations of the proposed approach are discussed.     

浅谈PMV方程的适用范围

近年来随着人们对居住环境热舒适度的重视,利用ISO7730标准中PMV-PPD指标来进行室内热环境舒适度评价的现象越来越普遍,目前许多研究室内热环境的文章也是把PMV-PPD指标作为参考和依据,来进行研究与分析。但是对于PMV-PPD指标的适用范围却很少有人关注和了解,从而出现了对PMV指标的误用和滥用,并推导出某些不准确的结论。通过对PMV方程推导过程的分析,解释了在高温条件下PMV指标与实际情况不符的现象,进一步说明PMV方程的适用范围,从而保证在进行热舒适度研究过程中可以作出科学合理的评价与结论。     

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。     

Occupants’ impact on indoor thermal comfort: a co-simulation study on stochastic control of solar shades

This paper investigates the impact of manually operated solar shades on indoor thermal comfort. A developed stochastic model for manual solar shades was modelled in Building Controls Virtual Test Bed, which was coupled with EnergyPlus for co-simulation. Movable solar shades were compared with two unshaded windows (clear double-pane and low-e double-pane). Two objective indices (room base temperature and transmitted solar radiation) and one subjective index (modified predicted mean vote (PMV) index (PMVrad) that considers solar radiation on the human body) were used to evaluate the indoor thermal performance. Results show that external solar shades achieve the best performance in terms of all three indices, especially for PMVrad, hours of comfortable conditions are higher than unshaded windows by 20.6–37.3%. Despite achieving relatively high performance, solar shades are operated infrequently and for about 30% of work time they are not adjusted appropriately, leading to a decrease in indoor thermal comfort.     

不同气流组织下夏季空调室内热舒适环境模拟

基于模型和Fanger提出的热舒适性PMV评价指标,对三种不同气流组织条件下夏季室内热舒适环境进行了数值模拟,模拟结果给出了室内的速度、温度及舒适度PMV指标分布情况。研究结论为改善室内热舒适环境,舒适性空调系统的设计及节能控制提供了参考依据。     

Building envelope regulations on thermal comfort in glass facade buildings and energy-saving potential for PMV-based comfort control

This paper presents an investigation of the effect of building envelope regulation on thermal comfort and on the energy-saving potential for PMV-based comfort control in glass facade buildings. Occurrences and severity of overheating, based on the PMV-PPD model contained in ISO 7730, were used for the thermal comfort assessment. Parametric study simulations for an actual building with a large glass facade were carried out to predict the changes in thermal comfort levels in a space due to different glazing types, depths of overhang and glazing areas, which are the key parameters of the building envelope regulation index, named ENVLOAD, in Taiwan. The result demonstrates that the ENVLOAD has significant effect on thermal comfort. Additionally, comparative simulations between PMV-based comfort control and conventional thermostatic control were performed to investigate the changes in the energy-saving potential of a thermal comfort-controlled space due to changes of its ENVLOAD. The results demonstrate that the energy-saving potential in a PMV-based controlled space increases with low ENVLOAD conditions.     

广西桂林龙胜地区干栏式建筑热舒适度的研究

随着对民族特色建筑的研究逐渐增多,对传统建筑研究的重要目的之一在于验证建筑物空间和形态与地区气候条件之间是否具有良好的适应性。通过对广西桂林地区少数民族干栏式建筑和普通居住建筑建筑参数、气象数据的实地测量,采用Design-Builder模拟软件对其建立模型,并进行CFD仿真,模拟得到建筑物内部的热环境以及全年室内温度,最终计算得出建筑物内部全年热舒适度指标。经对比仿真结果得出,干栏式建筑内部热环境和热舒适度指标明显优于普通居住建筑,干栏式建筑更加符合广西地区气候。     

套室内人体热舒适的研究

借助于通用流场计算软件PHOENICS，在考虑了外界气温、太阳的热辐射条件，家具以及人员等室内微气候影响的情况下，预测了两室一厅套室内气流三维流场和温度场。得到了套室内气流的速度、温度和人体热舒适指数等参数的分布，并经过评定，该套室内的热环境达到了人体的舒适性要求。模拟计算结果对套室的设计及其空调系统的配置具有重要的参考价值，并为套室内人体热舒适的进一步研究和室内空气品质问题的研究奠定了基础。     

基于舒适度指标楼盖结构竖向振动分析

就各国建筑规范中关于舒适度指标的楼盖振动的基本规定和当前主要的楼盖振动模型进行了介绍。通过对某超高层大楼楼盖的现场振动测试,对脉动情况下楼盖阻尼比进行了分析,并将振动峰值加速度实测结果与理论计算值进行了比较分析,对不同楼盖振动加固方法的效果进行了比较讨论,最后总结了基于舒适度指标的楼板振动控制设计中存在的不足和需要进一步研究的内容。     

送风角度对空调列车室内热舒适性的影响

本文以YW25G型空调硬卧列车为研究对象,采用LVEL湍流模型,模拟不同送风角度下的列车内温度场、速度场、空气龄、CO2浓度及热舒适指标PMV、PPD的分布情况,通过比较得到最佳送风角度,为改善列车室内的热舒适性提供参考依据.     

The effect of Urban Heat Island mitigation strategies on outdoor human thermal comfort in the city of Baghdad

Todays, most Iraqi cities suffer from extremely hot-dry climate for long periods throughout the year. However, most urban patterns that exist inside these cities are not suitable for this harsh conditions and lead to an increase in the value of the Urban Heat Island (UHI) index. Consequently, this will increase outdoor human thermal discomfort as well as energy consumption and air pollution in cities. This study attempts to evaluate the effect of UHI mitigation strategies on outdoor human thermal comfort in three different common types of urban patterns in the biggest and most populated city in Iraq, Baghdad. Three different mitigation strategies are used here – vegetation, cool materials, and urban geometry – to build 18 different scenarios. Three-dimensional numerical software ENVI-met 4.2 is utilised to analyse and assess the studied parameters. The input data for simulations process are based on two meteorological stations in Baghdad: Iraqi Meteorological Organization & Seismology, and Iraqi Agrometeorological Network. All measurements are taken in a pedestrian walkway. The results of different scenarios are compared based on their effect on human thermal comfort. Outdoor thermal comfort is assessed according to Predicted Mean Vote index, as mentioned in ISO 7730 standard. This study provides a better understanding of the role of UHI mitigation strategies on human thermal comfort in the outdoor spaces of Baghdad's residential neighbourhoods. This can help generate guidelines of urban design and planning practices for better thermal performance in hot and dry cities.     

关于"热感觉"与"热舒适"的讨论

对哈尔滨市居民的热感觉与热舒适状况的调查结果表明：热感觉投票值分布频率与热舒适投票值分布频率是有差异的。对新加坡现场调查结果的分析数据也表明：热感觉与热舒适是不同的,热感觉和热舒适既仔在于稳态热环境中又存在于动态热环境中。     

严寒地区居住建筑室内热舒适模拟研究

将模拟计算得到的模型房间的温度场与经回归分析建立的平均热感觉MTS预测模型和热舒适评价指标PMV相结合,通过编制MATLAB程序,绘制了模型房间不同截面的MTS和PMV的三维分布图。比较了各个截面的MTS和PMV预测结果并分析了产生误差的原因。     

基于投影寻踪的热舒适性评价模型

本文根据4个影响热舒适的主要因素(环境温度、风速、相对湿度和平均辐射温度),研究建立了热舒适评价的投影寻踪模型,利用该模型可将影响热舒适的多个指标转换为反映各指标综合信息的投影特征值,并根据投影特征值的差异性大小对热舒适进行客观评价。通过与实际环境的主观评价相比较,表明其评判结果与主观感受是一致的。这种方法计算简单、方便实用,为室内环境热舒适的评价问题提供了一条新的方法与思路。     

广州典型城中村住宅室内热环境测试与分析

本文以通过筛选所得到的广州市某城中村3户民居作为测试对象,对最具代表性的城中村住宅夏季室内环境参数进行了测试。而后,使用预测平均评价指标(PMV)和适应性热舒适模型(AM)对比分析了城中村不同类型住宅室内热湿环境特性和室内热舒适状况。研究结果表明AM模型更适合城中村民居的室内热舒适性评价。另外,用此2种模式进行评价,其结果都是住宅室内温度越高、湿度越大、空气焓值越大,热舒适接受率越低。     

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。     

校园行道树对夏季室外行人热舒适的 影响研究

道路绿地作为城市绿地的重要组成部分,在缓解城市热岛和改善行人热舒适等方面起着重要作用。通过监测大学校园内7种典型行道树树荫和阳光下的空气温度(T_a)、相对湿度(RH)、风速(V_a)、黑球温度(T_g)和太阳辐射(G)等气象参数以及行道树的叶表面温度(T_(1s),运用通用热气候指数(Universal Thermal Climate Index,UTCI)分析不同行道树对道路空间热环境的影响和行人热舒适的改善效果。结论如下:1)行道树改善道路空间行人热舒适作用明显,对T_a和平均辐射温度(Mean Radiant Temperature,T_(mrt)降低能力最强的树种分别为悬铃木和银杏;2)天空可视因子(Sky View Factor,SVF)是影响道路空间行人热舒适的主要因素;3)T_(1s)与UTCI呈强线性正相关(R~2=0.8083),夏季T_(1s)越高,道路空间行人热舒适度越差。研究结果从室外热舒适评价的角度为行道树设计提供了理论基础和量化指导。     

基于SET舒适指标的控制器

介绍了基于SET舒适指标控制器模型的基本组成和建立方式,从系统设计、硬件组成、控制系统软件三方面阐述了该控制器参数的采集和控制原理,从而实现对室内热舒适的控制,并为节能研究提供了重要条件。     

基于生理指标评价人体热舒适、工作效率和长期健康的研究路线探讨

分析了人体在热环境中的生理响应机制,综述了国内外基于生理指标的人体热舒适、工作效率和长期健康的研究现状,指出生理指标在评价工作效率和人体健康方面具有重要价值,但对于热舒适研究只能作为一个辅助评价指标,并提出了生理指标在评价热舒适、工作效率和人体健康方面的研究路线。     

最小二乘支持向量机在热舒适性指标中的应用

本文介绍了最小二乘支持向量机的原理,并针对热舒适性指标建立了最小二乘支持向量机预测模型,以人的新陈代谢率、衣服热阻、空气温度、相对湿度、平均辐射温度和空气流速作为输入变量,以PMV指标作为输出。该模型计算结果与Fanger方程的计算结果吻合很好,与BP神经网络模型及传统的支持向量回归机模型进行分析比较的结果表明最小二乘支持向量机模型具有较高的拟合精度和泛化能力,可以满足PMV指标作为被控参数对空调系统进行实时控制的要求。