内蒙古中南部农牧区居民过渡季热舒适研究

以内蒙古中南部地区乌兰察布周边某农牧区为例,通过现场跟踪测试和主观调查相结合的方法,采用平均热感觉指数(predicted mean vote, PMV)和平均热感觉投票值(mean thermal sensation vote, MTS)以及热中性温度等指标,分析了生土民居、砖瓦民居、民生工程民居在过渡季的人体热舒适性。结果表明：在过渡季,三种民居中MTS与PMV存在偏差,但整体均为MTS高于PMV,说明居民能够适应温度较低环境;生土民居、砖瓦民居、民生工程民居的实测热中性温度分别为15.90、16.60和18.80℃,预测热中性温度和实测差值分别为2.10、1.90和1.20℃,民生工程民居差值最小,说明其室内热环境优于砖瓦民居和生土民居;对农牧区居民80%和90%实测热中性温度范围与室外日平均温度回归分析,得出适宜当地居民过渡季的人体热舒适模型,为研究农牧区居民在过渡季的热舒适性提供参考。     

桂林高校宿舍夏季室内热环境调查研究

以桂林高校5间宿舍为研究对象,对学生宿舍室内外空气温度、相对湿度、空气流速以及太阳辐射等环境参数进行现场测量。并结合问卷调查方式对受试者的服装热阻、热感觉、湿感觉、吹风感等进行统计分析。结果表明宿舍室内热湿环境不能被大多数学生接受,学生普遍通过减少着装等方式适应湿热气候但热中性温度仍然偏高,对温度的敏感程度较高,此研究结果与其他湿热地区相近。针对该地区独特的气候特征,采用建筑设计与遮阳措施相结合的节能措施,为进一步完善湿热地区宿舍热环境评价与设计提供参考。     

基于性别的严寒地区高校教学楼自然通风热舒适性研究

严寒地区夏季采用自然通风作为被动式降温手段,改善空气品质的同时减少能耗,其热舒适性会受到多因素影响。对严寒地区夏季自然通风条件下两种建筑布局的高校教学楼热环境进行实测,对影响热舒适的三种因素,温度、湿度以及受试者体重指数(bady mass index,BMI)进行调查研究,基于在室人员不同性别,进行差异性、相关性和显著性对比分析。结果表明:内廊式教学楼较中庭式教学楼有更好的热舒适性;操作温度与热舒适性密切相关,中性温度为27.96℃,其中男性为27.51℃,女性为28.26℃;相对湿度与操作温度负相关,且对热舒适性有较大影响;BMI与热舒适性呈现较低的相关性,其并不能明显影响热舒适性,但相同BMI下,男性热感觉略高于女性;利用Griffiths评价模型能准确预测严寒地区夏季舒适温度。     

桂林某高校学生公寓夏季室内热舒适调查研究

以桂林某高校学生公寓楼顶层的3间学生宿舍为调查对象,对其夏季室内外温湿度、室内空气流速、室内黑球温度等参数进行了现场测试,同时以问卷形式调查了学生对室内热环境的主观热感觉。通过对测试的参数及热舒适的影响因素进行分析,结果表明:长廊式结构导致宿舍通风散热效果差,长廊两端的宿舍热环境相比中间部分宿舍有一定的差异,绝大部分学生对室内热环境有较强的适应性,会通过一些适应性行为来改善自身热感觉。本研究旨在为桂林高校宿舍热环境的研究和改善提供参考。     

秦岭山区民居冬季室内热环境测试

为考察秦岭山地民居冬季室内热舒适状况,选取当地典型二层生土和砖砌民居作为研究对象,对其冬季室内温度、相对湿度、室内照度和壁面温度进行现场测试并记录室外温湿度与太阳辐射强度.通过对测试数据分析,给出了不同外围护材料下民居室内热环境的定量评价,在此基础上提出改进其室内热环境的建议.     

桂林市某高校教学楼冬季室内热环境和热舒适性调查研究

以桂林市某高校教学楼第3层的4间教室为研究对象，对冬季室内热环境和学生的热舒适性感觉进行为期两天的直接测量和问卷调查，并对结果进行分析。结果表明：桂林高校教室冬季普遍温度过低且相对湿度较大，室内引入的新风量少、闷感强烈导致热环境较差；大部分学生对环境具有一定的适应能力，通过采取一些适应性行为调节自身的热舒适程度；桂林高校教室非空调环境下，冬季中性温度为19.9℃，期望温度为20.7℃。     

公共建筑环境因素对热舒适性的影响

利用热舒适仪现场测试了公共建筑人体的热舒指标PMV、温湿度等参数,分析了这些参数对人体舒适性的影响,改善夏季人体热舒适性,为我国的空调节能政策提供依据和方法。研究结果表明室内空气温度是影响人体舒适性最主要的因素,相对湿度在60%时,温度每升高1℃。PMV值约增加0.3;室内温度在26℃时,相对湿度每升高10%,PMV值约增加0.1,由此可见相对湿度对人体舒适性的影响不容忽视。     

室内自然通风环境热舒适性研究

通过建立室内自然通风模型,研究了系统在不同温度、不同进风口风速及不同外窗开度情况耦合工况下,人体热舒适感受能够承受的温度上限和空气流速与外窗开度的适用范围。结果表明,室内热舒适性会随室外温度升高而明显恶化,温度达28.5℃时超过热舒适性指标国家标准推荐值;各因子中,风速及温度对室内热舒适性影响比重相对较轻,外窗开度的影响最大;20%为外窗开度下限,随开度的增大室内热舒适性增强;风速增加带来的不适"吹风感"也需考虑,该个体差异性感受会使得室内热舒适性迅速下降。     

办公建筑蓄热和夜间通风的实验研究

以西安地区既有办公建筑为研究对象,主要研究蓄热和夜间通风对建筑室内热环境的影响。由7月22日至8月9日的实验结果可知,采用夜间通风措施与未采用通风措施房间的平均室内温度差值为1℃,最大差值超过2℃,采用蓄热措施后其室内温度可在此基础上进一步降低约3℃。通过分析室内温度变化频率可知,大部分时间实验房室内温度超过28℃;采用蓄热措施后,其中仅有21%的时间室内温度高于28℃;而采用蓄热体和夜间通风综合措施时,仅有4%的时间其室内温度超过28℃。因此,如果办公建筑室内热舒适上限温度为28℃,那么有96%的时间可以在不使用空调设备的情况下达到室内热舒适状态。     

室内动态热舒适的影响因素分析

析了室内动态热环境下人体热舒适的主要影响因素,并探讨了不同因素的影响程度,指出室内动态热环境下人体热舒适性是各种因素综合作用的结果,室内空气温度、气流速度、空气相对湿度、平均辐射温度、人体生理心理特点、人体活动量、服装参数等均对动态热舒适有影响,其中空气温度及气流速度的动态化是其影响的主要客观因素,人体条件及服装参数是主要主观因素。     

火电厂节能工作浅析

本文探讨了火电厂节能基本程序和工作方法,分析节能工作要从基础工作、技术创新、设备整治、燃烧管理等方面入手的论述.     

浅析磨合期汽车的使用

如何合理使用磨合期的汽车，使其摩擦机件的磨损量能够平稳、均匀地磨合而不至于过度磨损，对汽车实际使用寿命有着重要的意义。从机器磨合期的特点和磨损机理出发，对汽车磨合期如何正确使用进行了有实际意义的探讨。     

Geothermal energy in agriculture in Yugoslavia

SFR Yugoslavia has natural hot water springs practically all over its territory, indicating the presence of geothermal reservoirs underground. There is no final estimate of how much energy can be expected from this new resource, except for figures based on the results of studies and investigations.The first use of geothermal energy in Yugoslavia in numerous spas dates back to the 19th century. Some remarkable examples of central heating are known, but the most widespread use is in agriculture (in greenhouse heating, farm heating and drying of agricultural products).     

Energy conservation measures in an institutional building in sub-tropical climate in Australia

In this study, various energy conservation measures (ECMs) on heating, ventilating and air conditioning (HVAC) and lighting systems for a four-storied institutional building in sub-tropical (hot and humid climate) Queensland, Australia are evaluated using the simulation software called DesignBuilder (DB). Base case scenario of energy consumption profiles of existing systems are analysed and simulated first then, the simulated results are verified by on-site measured data. Three categories of ECMs, namely major investment ECMs (variable air volume (VAV) systems against constant air volume (CAV); and low coefficient of performance (COP) chillers against high COP chillers); minor investment ECMs (photo electric dimming control system against general lighting, and double glazed low emittance windows against single-glazed windows) and zero investment ECMs (reset heating and cooling set point temperatures) are evaluated. It is found that the building considered in this study can save up to 41.87% energy without compromising occupancies thermal comfort by implementing the above mentioned ECMs into the existing system.     

Leading-edge Technologies in Hydropower Development in China

After the implementation of the Reform and Opening-up Policy for a period of 40 years, the exploitation of China’s hydropower resources developed significantly. Through vast amounts of scientific and technological research and construction practices, China has accumulated abundant engineering experience with respect to the construction technologies required for 300-meter-high concrete arch dams, 200-meter-high roller-compacted concrete gravity dams, 200-meter-high concrete face rockfill dams, and 250-meter-high earth core rockfill dams, large-flow discharge and energy dissipation, huge underground cavern group constructions, complicated foundation treatments for high earth and rockfill dams and high and steep slope reinforcements. These series of technologies have now reached an international leading level. In the near future, these technical improvements will likely have broader application prospects and make greater contributions toward hydropower development both in China and across the world.     

Uncertainties in decarbonising heat in the UK

Heating is arguably one of the most difficult sectors to decarbonise in the UK's energy system. Meeting the 80% greenhouse gas emission reduction target by 2050 is likely to require that heat related emissions of CO₂ from buildings are near zero by 2050, and there is a 70% reduction in emissions from industry (from 1990 levels). Though it is clear that the use of the natural gas network will reduce over time, recent modelling suggests a limited residual role for gas by 2050 to help meet peaks in heat demand. High levels of uncertainty about the way in which heat will be decarbonised present a number of challenges to policy makers. This paper will explore the risks and uncertainties associated with the transition to a low carbon heat system in the UK as outlined by the 4th carbon budget review. The potential impact of key uncertainties on the levelised costs of heat technologies and the development of energy networks are explored using a sensitivity analysis approach. Policy changes required to decarbonise the heat sector are also examined.     

Viscous heating in liquid flows in micro-channels

Many experimental works on forced convection through micro-channels evidenced that when the hydraulic diameter is less than 1 mm, conventional theory can no longer be considered as suitable to predict the pressure drop and convective heat transfer coefficients. This conclusion seemed valid for both gas and liquid flows. Sometimes the authors justified this claim by invoking “new” micro-effects. On the contrary, in this paper the explanation of the experimental results obtained for micro-channels in terms of friction factors will be researched inside the conventional theory (Navier-Stokes equations). In particular, this paper will focus on the role of viscous heating in fluids flowing through micro-channels. A criterion will be presented to draw the limit of significance for viscous dissipation effects in micro-channel flows. The role of the cross-sectional geometry on viscous dissipation will be highlighted and the minimum Reynolds number for which viscous dissipation effects can no longer be neglected will be calculated as a function of the hydraulic diameter and of the micro-channel geometry for different fluids. It will be demonstrated how viscous effects can explain some experimental results on the Poiseuille numbers in micro-channels, which recently appeared in the open literature.     

Solar drying in sludge management in Turkey

Two main wastewater treatment plants in Bursa city in Turkey will start to operate and produce at least 27,000 tons of dry solids per year by the end of 2006. The purpose of this study was to investigate an economical solution to the sludge management problem that Bursa city would encounter. The general trend in Turkey is mechanical dewatering to obtain a dry solid (DS) content of 20%, and liming the mechanically dewatered sludge to reach the legal landfilling requirement, 35% DS content. This study recommends limited liming & solar drying as an alternative to only-liming the mechanically dewatered sludge. Open and covered solar sludge drying plants were constructed in pilot scale for experimental purposes. Dry solids and climatic conditions were constantly measured. Faecal coliform reduction was also monitored. The specially designed covered solar drying plant proved to be more efficient than the open plant in terms of drying and faecal coliform reduction. It was found that, if the limited liming & solar drying method was applied after mechanical dewatering instead of only-liming method, the total amount of the sludge to be disposed would be reduced by approximately 40%. This would lead to a reduction in the transportation, handling, and landfilling costs. The covered drying system would amortize itself in 4 years.     

Electoral cycles in electricity losses in India

A third of electricity in India is lost each year, where losses refer to power that is supplied but not billed. Utilizing data from the power corporation of Uttar Pradesh, India's most populous state, we study the politics of electricity losses. Examining annual data over four decades, we document that UP's electricity losses tend to increase in periods immediately prior to state assembly elections. Drawing upon geographically disaggregated data for the period 2000–09, we observe higher line losses just prior to the 2002 and 2007 state elections. Our analysis shows that the incumbent party was more likely to retain the assembly seat as line losses in the locality increased. We interpret these results as corroboration that political parties deliberately redirect electricity to flat rate and unbilled users in a context of chronically inadequate supply. Political factors appear to affect line losses in ways that technical and economic factors alone cannot explain.