Adaptive use of natural ventilation for thermal comfort in Indian apartments

Thermal comfort research in India is in its nascent stage. Indian codes specify uniform comfort temperatures between 23 and 26 °C for all types of buildings. About 73% of energy in Indian residences is consumed for ventilation and lighting controls. Therefore, a thermal comfort field survey was conducted in apartment buildings in Hyderabad, which included information on the use of building controls. The present analysis is based on this database. Due to the poor availability of adaptive opportunities, 60% of the occupants were uncomfortable in summer. The comfort range obtained (26.0–32.5 °C) was way above the standard.     

Investigation of indoor thermal comfort under transient conditions

In industrialized countries about 90% of the time is spent indoors. In indoor, thermal comfort can be basically predicted by the environmental parameters such as temperature, humidity, air velocity and by the personal parameters as activity and clothing resistance. In this study, a mathematical model of thermal interaction between human body and environment was established and the effect of clothing and air velocity was examined under transient conditions. By the developed model, human body has been separated to 16 segments and possible local discomforts are taken into consideration. Using the model, changes in the sensible and latent heat losses, skin temperature and wettedness, thermal comfort indices were calculated. In a hot environment latent heat loss increases by means of sweating. Because of over wetted skin, comfort sense goes worse. Especially, at feet and pelvis skin wettedness reaches maximum level. Sensible and latent heat losses rise and the skin temperature and wettedness decrease with increasing air velocity.     

外墙外保温系统对室内热舒适性的影响

在相同的外界条件下,测试外保温房和未保温房室内的温度和湿度,分析室内的热舒适性。分析结果表明,外保温房的室内舒适性评价指标PMV-PPD(PredictedMeanVote-PredictedPercentDissatisfied)值在舒适值附近波动的幅度明显小于未保温实验房,外墙外保温系统提高了室内的热舒适性。     

Behavioural adaptation and the use of environmental controls in summer for thermal comfort in apartments in India

Building energy use in India is rising phenomenally. Indian codes prescribe a very narrow comfort temperature range (23-26 °C) for summer. Ventilation controls alone consume 47% of total energy in residences. Thermal comfort field studies in Indian residences were not attempted. The author conducted a field study in apartments in Hyderabad, in summer and monsoon seasons in 2008. This paper presents the occupants’ methods of environmental and behavioural adaptation and impediments in using controls.Only about 40% of the occupants were comfortable in summer due to inadequate adaptive opportunities. The comfort range obtained in this study (26.0-32.5 °C), was way above the standard. Fanger's PMV always overestimated the actual sensation.The occupants used many adaptation methods: the environmental controls, clothing, metabolism and many behavioural actions. Use of fans, air coolers and A/cs increased with temperature, and was impeded by their poor efficacy and noise, occupant's attitudes and economic affordability. A/c and air cooler usage was higher in top floors. Behavioural adaptation was better in summer and was restricted in higher economic groups always. Thermal tolerance was limited in subjects using A/cs and resulted in “thermal indulgence”. This study calls for special adaptation methods for top-floor flats.     

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.     

The impacts of ventilation strategies and facade on indoor thermal environment for naturally ventilated residential buildings in Singapore

The impacts of various ventilation strategies and facade designs on indoor thermal environment for naturally ventilated residential buildings in Singapore are investigated in this study based on thermal comfort index. Four ventilation strategies, nighttime-only ventilation, daytime-only ventilation, full-day ventilation and no ventilation were evaluated for hot-humid climate according to the number of thermal discomfort hours in the whole typical year on the basis of a series of TAS simulations. Parametric studies of facade designs on orientations, window to wall ratios and shading devices were performed for two typical weeks by coupled simulations between building simulation ESP-r and CFD (FLUENT). The results indicate that full-day ventilation for indoor thermal comfort is better than the other three ventilation strategies. With various facade design studies, it was found that north- and south-facing facades can provide much comfortable indoor environment than east- and west-facing facades in Singapore. It is recommended that optimum window to wall ratio 0.24 can improve indoor thermal comfort for full-day ventilation and 600 mm horizontal shading devices are needed for each orientation in order to improve thermal comfort in further.     

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。     

北京地区大学教室热舒适长期调查研究

针对北京市某大学的教室进行调研,对室内热环境参数、受访者服装热阻及受访者热感觉投票进行了为期1年的跟踪调查。试图通过探索教室热环境参数与受访者热感觉之间的关系了解受访者对教室内热环境的需求,结果发现,不同季节受访者对环境的需求存在差异,夏季空调环境人体中性温度为26.9℃,过渡季节自然通风环境中性温度为23.5℃,而冬季集中供热环境中性温度为22.9℃,着装量不同是造成上述差异的主要原因。对于室内环境控制,在春秋过渡季节的绝大多数时间,自然通风可满足人员对室内热环境的需求;在非自然通风季节,将室内温度控制到可接受的范围就可以满足多数受访者的需求。     

通风降温建筑室内热环境模拟及热舒适研究

将热舒适评价标准ＰＭＶ／ＰＰＤ模型与建筑动态热模拟及计算流体动力学（ＣＦＤ）模拟相结合，分别对重庆地区自然通风房间和埋管送风通风房间进行了室内气候及热舒适性模拟与分析，结果表明，埋管系统通风降温可以改善炎热地区的室内热舒适性。     

热舒适评价指标及冬季室内计算温度探讨

以Fanger热舒适方程及PMWV，PPD评价指标为理论依据，模拟计算了严寒地区居室热环境，结果表明，满足人体热舒适的室内空气温度为21－24℃，明显高于现行暖通规范规定的冬季居室内计算温度16－20℃。认为应研究适于我国严寒地区居民的热舒适标准。     

Natural ventilation potential for gymnasia-Case study of ventilation and comfort in a multisport facility in northeastern United States

The natural ventilation potential to maintain acceptable indoor air quality(IAQ) and thermal comfort in gymnasia was investigated using a university multisport facility in northeastern United States as a case study building. A parametric modeling study was conducted considering the effects of opening configurations and control strategies during the summer months. The thermal accuracy of the model was verified using field measurements during August 2015. Performance metrics for IAQ and thermal comfort were the percentages of occupied hours during which ventilation rate met or exceeded ASHRAE Standard 62.1-2013 and temperature met adaptive thermal comfort criteria of ASHRAE Standard55-2013, respectively. Wind direction was found having a major effect on cross ventilation rate. Wind and buoyancy driven forces could complement or oppose each other depending on the wind direction and opening position. Relative to the base case, larger net openings that were more evenly distributed performed better.Rooftop vents improved ventilation performance, particularly under unfavorable wind conditions. With improved opening configurations, the acceptable ventilation hours increased from 21.5% to99.5% of occupied time for the maximum occupancy. The strictest temperature-controlled strategy had the best thermal performance.Thermal comfort conditions could be maintained during 85.3% of the occupied hours. However, the temperature rule largely shortened the opening operation time, and consequently decreased the acceptable ventilation hours to only 47.1%. Continuously natural ventilation during occupied time gave the longest combined IAQ-thermal acceptable hours, 73.9% of the occupied time, although it moderately decreased the thermal comfort hours to74.2%.     

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。     

供暖房间热舒适模糊分析及最优室内计算温度的研究

模拟我国中部地区冬季供暖房间热微环境及人员衣着习惯,针对钢制柱式、钢制串片和钢制扁管三种典型供暖散热器,进行了人体热舒适实验,并对实验结果进行了模糊分析。得到了适用于我国中部地区供暖设计及运行的室内计算温度,其最优范围为１７．０～１９．２℃。通过对实验结果的分析,提出供暖散热器的改进方向。     

Conditioning strategies of indoor thermal environment in warm climates

Commenting on some negative effects of traditional conditioning strategies of indoor thermal environment in warm climates, the authors present a fundamental concept of thermal comfort and acceptability, new air-conditioning strategies by using fluctuating air movement based on the findings of human responses to transient thermal environment, and a prediction of energy saving caused by elevated indoor temperature settings. In addition, how to meet the requirement of providing human-beings a healthy, comfortable and affordable indoor air temperature, and to achieve a goal of sustainable development are also discussed in this paper.     

由热舒适指标及空调设计计算参数谈节能

以PMV—PPD评价指标和ASHRAE舒适标准为理论依据，对空调设计舒适度和空调节能进行了讨论，认为应研究适于我国居民的热舒适标准，而后提出一些节能措施以及方向。     

Virtual Building Dataset for energy and indoor thermal comfort benchmarking of office buildings in Greece

The knowledge of building stock energy data of a country is a very significant tool for energy benchmarks establishment, energy rating procedures and building classification boundaries determination, according to the Directive 2002/91/EC and its implementation in EU Member States. The lack of building energy databases in many EU Countries, including Greece, and the difficulties of collecting them lead to the investigation of other potential solutions. The aim of this paper is to present a method of a Virtual Building Dataset (VBD) creation for office buildings in Greece. The philosophy of VBD is based on the creation and simulation of random office buildings that could be found or built in Greece, taking into account the Greek constructional and operational characteristics of office buildings and Greek legislation. The VBD consists of 30,000 buildings (10,000 in each climatic zone) with their detailed constructional and operational data and of their simulation outputs: the annual specific energy consumption for heating, cooling, artificial lighting, office equipment and an indoor thermal comfort indicator. Based on VBD results the energy and indoor thermal comfort benchmarks for office building sector in Greece are assessed and presented.     

自然通风与节能舒适性分析

介绍了自然通风技术的基本原理与应用形式,从建筑物节能与舒适性两方面探讨了自然通风在建筑物中的应用,指出在自然通风的设计和应用过程中应综合考虑地理气候、建筑物结构和环境调节要求等因素,同时应加强相关技术的研究和开发。     

哈尔滨地区冬季农宅热舒适现场调查

对哈尔滨近郊2个村10户农宅的冬季室内热环境与居民的热舒适进行了现场调查。结果显示,冬季农宅的平均室温为12.3℃,但热环境可接受率高达92%;农民的热中性作业温度为14.4℃,90%可接受的作业温度下限为8.8℃;农民通过行为调节、心理期望等适应偏冷的热环境,导致其热中性温度与可接受的温度较低。对于分散式农宅,建议采用传统的火炕分散供暖方式。建议采用作业温度作为严寒地区冬季农宅室内热舒适的评价指标。