首届中国清洁技术投融资峰会在北京举行

随着中国经济的飞速发展,能源短缺,环境污染等问题日益严重.欧美等发达国家早已开始着手解决这些问题,每年都有大量来自于政府、企业和风险投资的资金用于清洁技术的研究与应用.根据道琼斯数据显示,2007年在清洁技术领域,全球共发生了221项投资案例,投资总额达30亿美元,比2006年增长了43%.     

中国科技部长万钢获国际氢能大奖

第十七届世界国际氢能大会于2008年6月15日～19日在澳大利亚布里斯班市举行,来自全世界44个国家的600余位代表聚集一堂,讨论当代氧能技术和发展趋势.     

Experimental Investigation on the Adiabatic Film Effectiveness for Counter-Inclined Simple and Laid-Back Film-Holes of Leading Edge

The adiabatic film effectiveness η of the counter-inclined film-holes fed by varying internal coolant intake on the turbine vane leading edge model was experimentally investigated. A semi-cylinder model was adopted to model the vane leading edge which was arranged with two-row holes, which located at ±15° on both sides. The four Leading edge model with the combinations of hole-shape(simple holes and laid-back holes) and intake structure(plenum and impingement) were tested under four blowing rati...     

国家发展改革委、财政部、国家电监会要求各地限期全面落实差别电价政策

经国务院批准,国家发展改革委、财政部、国家电监会近日联合下发了《关于进一步贯彻落实差别电价政策有关问题的通知》(以下简称《通知》),要求各地限期全面落实差别电价政策.     

热泵辅助太阳能中央热水系统年运行特性研究

提出采用热泵来取代传统的电加热器,构成热泵辅助太阳能中央热水系统,可有效地降低能源消耗.结合2005年西安地区气象数据,建立了合适的数学模型,并用现有的试验数据对模型进行了校准,通过模型模拟了该年热泵辅助和电辅助太阳能中央热水系统的性能系数,输入功耗,出水温度等运行参数,并对两者进行了对比.     

第二讲认识太阳利用太阳

一、太阳与太阳能 众所周知,在浩翰的宇宙中有一颗离我们最近的恒星--太阳.现代科学表明太阳距离我们相当遥远,达到1.5亿km,虽然太阳光的传播速度为30万km/s,但我们在地球上所见到的光线已经是8min之前从太阳发出的光线了.太阳的直径为139万km,而地球直径仅为1.27万km,太阳的直径约为地球直径的109倍,其体积则比地球大130多万倍.尽管如此,由于距离遥远,太阳张角仅仅为32′.     

Numerical Study of Convective and Radiation Heat Transfer Characteristics in an Upward-Facing Cylindrical Cavity under Back-Side Windy Condition

Under the back-side windy condition,the convection and radiation heat transfer characteristics in an iso-flux upward-facing cylindrical cavity were studied by three-dimensional numerical simulation.The impacts of cavity tilt angle,wind incident angle and wind speed on convection and radiation heat transfer Nusselt number Nuc and Nur were analyzed,and the possible explanations for their impacts were presented.Results show that due to the disturbance of wind,the influence of cavity tilt angle becomes more complicated and is related to wind incident angle and wind speed.The variation of Nuc or Nur with wind incident angle is different for different cavity tilt angles.Despite of the changes of cavity tilt angle or wind incident angle,the Nuc increases with the wind speed while the Nur presents a declination with the increasing of wind speed.Hence,compared with cavity tilt angle and wind incident angle,wind speed may be the dominant factor affecting or controlling the convective and radiation heat transfer of cavity.     

太阳能干燥系列讲座(1)太阳能干燥——太阳能热利用中不可忽视的领域

一物料干燥的能耗与环境污染 干燥作业涉及国民经济的广泛领域,是许多行业不可缺少的工序.在粮食、食品、果品、药材、木材、皮革、橡胶和陶瓷等许多产品的加工处理过程中,干燥作业对产品的质量和成本影响很大.     

担当

<正>6月30日,当中国政府将《强化应对气候变化行动——中国国家自主贡献》提交给联合国气候变化框架公约秘书处后,全世界都为中国的决定而侧目。中国设定了一个宏大的减排目标,振奋了各国应对气候变暖的神经。潘基文在声明中称赞中国提出的方案为在巴黎气候变化大会上增加动力、增强互信起到了积极推动作用;联合国秘书长副发言人哈克表示,中国提交自主贡献文件,为巴黎气候大会达成新的气候变化协议注入了动力,     

户用小型风力发电系统现状与发展(上)

<中华人民共和国可再生能源法>已于2005年2月28日在全国人大第11届第14次会议上通过,并将于2006年1月1日起施行,该法的颁布和实施,给小型风力发电行业的发展带来希望和光明,也必将大大促进农村能源的发展,户用风力发电产业也将会更上一层楼,前景看好.     

The effects of air leaks on solar air collector behaviour

The construction of conventinal solar air collectors and the fact that they will operate with a significant pressure difference between the heated air stream and ambient, suggests that significant quantities of air may leak into or out of them. A search of the literature reveals no consideration of the effects these air leaks may have on the validity of collector efficiency measurements, on the efficiency itself, or indeed what the meaning of efficiency is under such operating conditions. This paper discusses the meaning of collector efficiency when leaks into the collector occur, analyses the effects on efficiency measurements, and solves the collector efficiency for the simple case of a constant leakage rate along the collector. Assuming that air leaking in from ambient can replace deliberate fresh air supply to the load as in building heating, then significant measurement errors are made if air leaks in to the collector are not accounted for. Further, the collector efficiency is increased over the no leak case, so that complex construction methods to make the collector air tight are probably not warranted.     

空气湿度对平板空气集热器效率的影响

对不同相对湿度下的湿空气密度、定压比热容、动力粘度和导热系数等热物性参数进行了计算。在给定的平板空气集热器模型下计算得出,工作介质为相对湿度50%的湿空气比工作介质为干空气的集热器效率高12.4%。文章研究分析了太阳辐射量、空气通道高度、入口空气流速及温度对平板空气集热器顶部损失系数和效率的影响,研究结果显示,它们对介质为干空气及介质为湿空气的集热器影响趋势一致。     

Effect of air leak on long term performance of air heater

In this paper, the effect of an air leak on the air heater performance is investigated. “Air leaking in” and “air leaking out” systems are examined. The effect of various parameters like leakage rate, mass flow rate, solar insolation, plate length and ambient temperature has been studied. The possibility that air leakage can take place from any where along the length of the collector has been incorporated in the model. It is found that, for “air leaking in” systems, efficiency goes up, while for “air leaking out” systems, efficiency decreases from the no-leak situation, and it depends on the position of the leak.     

地道风系统地埋管管径对出口空气温度的影响研究

构建了空气与地道壁面换热理论模型,用于计算地埋管出口空气温度,通过正交模拟分析了地埋管管径、长度以及进口风速对地埋管出口空气温度的影响,并与数值模拟结果进行对比.结果 表明:地埋管管径极差值最大,可达20.4 m,是地埋管出口空气温度的主要影响因素,地埋管长度和进口风速为次要因素;随着管径的增大,出口空气温度随之升高;...     

改双管定风量系统为变风量系统的方法

在双管定风量系统中 ,不改变它的末端装置 ,而是在供热干管上安装热风阀 ,就能将双管定风量系统转变成变风量系统     

CFB锅炉空气预热器进风加热方式的探讨

分析了CFB锅炉几种空气预热器进风加热方式的优缺点 ,提出适合CFB锅炉的空气预热器进风加热方式。     

空调系统排风热回收换热器的试验研究

对用于回收空调系统余热的通风换热器进行了试验研究。在冬季工况下对其进行了性能测试。试验结果表明，该换热器具有换热效率高、阻力小的特点；在风速为2．6m/s的工况下，其换热效率达到64．5％。     

CFD investigation on the effect of air temperature on air blowing cooling system for preventing tube rupture

In this study a solution for preventing tube rupture in the superheater region of the 320 MW Bisotoun power plant boiler, Iran, was suggested. Based on our previous study, the air blowing system which locally cools the tube in place of tube rupture was proposed. Due to huge differences in air temperature at different seasons in the region the air with different inlet temperatures was blown over the modeled tube. The CFD results showed that the inlet air temperature has no significant effect on cooling performance due to high rate of heat transfer to the air carrier tube.     

新风量、送风方式和空调病症

本文叙述了新风量的大小和送风方式的不同与空调病症之间的关系。