海口市某高级酒店全年运行能耗统计与分析

对海口市某高级酒店的全年运行能耗进行统计分析,结果表明:该酒店单位面积总能耗为167.6k Wh/(m~2·a),其中单位面积总用电量为150.9k Wh/(m~2·a),所占比例为90.1%,在该地区处于中等偏高比例水平。酒店月用电量与月平均气温变化趋势基本一致,月用水量与月平均最低气温变化趋势更为接近,而月用气量与月平均入住率变化趋势基本一致。空调系统用电量占总用电量的比例为50.9%,机组经常处于低负荷运行状态,平均负荷率仅68.6%,是造成空调系统用电量偏高的重要原因之一,且在夏热冬暖地区酒店类建筑能耗中具有普遍性,存在较大的节能潜力,为类似气候地区酒店建筑的综合节能改造与优化运行管理提供有益的技术参考。     

办公建筑空调系统能耗评价及节能潜力分析

本文根据长沙市一办公建筑空调系统的全年运行记录和实测数据,分析了空调系统的能耗特征.并用温频数(BIN)法计算了空调年假想负荷及空调系统年能耗.用空调能耗系数CEC评价了空调系统的运行情况.在此基础上,从空调机组、水系统的运行管理及室内空气参数的设定三个方面进一步对空调系统进行节能潜力分析.结果标明,(1)在空调系统全年实际能耗量中,冷热水机组能耗高达54%,末端设备能耗为25%,水系统的能耗也高达21%.(2)该宾馆CEC系数为2.0,比日本的办公楼CEC的判断基准1.5大30%以上.这说明该办公楼空调系统能量利用效率较低,存在很大节能潜力.(3)空调机组和水系统的科学运行管理及室内空气参数的合理设定对该空调系统节能具有重大意义:笔者通过比较当负荷率在80%下,开启一台主机和同时开启两主机的能耗情况发现,开启一台主机,系统的总EER提高近23%.空调系统的总功率也可以减小25.9 kW;而和该空调设定温度25℃,相对湿度50%的情况相比,当空调设定温度提高到26℃,相对湿度提高到60%,空调能耗可节省6%.     

上海地区某地源热泵项目全年性能的实测研究

对上海地区某高层住宅楼应用的地源热泵系统的实际性能进行研究,检测系统逐日、逐月及全年的空调和热水能耗。结果表明:在现有入住率较低的情况下,3栋楼每户年平均能耗分别为52.5、72.0和83.4 MWh;空调热泵和热水热泵机组待机率分别超过了58%和81%;供暖、制冷和过渡季热水能耗分别占总能耗的70%、55%和90%。热泵机组长期低负荷运行且频繁启停,及水泵全年工频不间断运行是导致全年能耗偏高的主要原因。如何降低热水系统能耗是系统节能的关键之一。可采取所有热泵机组形成环网、水泵顺序启停和变频运行,并根据热水器内温度设定热水热泵主机启停等针对性措施,实现系统节能降耗。     

带低压补气的纯电动汽车空调系统制冷性能研究

为了解决纯电动汽车空调系统在夏季制冷时,由于压缩机排气温度较高所带来的系统制冷性能严重衰减、甚至不能稳定运行的问题,采用低压补气技术,设计了带补气的纯电动汽车热泵空调系统,并搭建了纯电动汽车性能测试实验台。基于R410A制冷剂,研究了压缩机转速在3000~5 000 r/min和环境温度在21~50℃分别变化时,低压补气系统与不补气系统性能的变化。结果表明：在环境温度35.00℃时,低压补气系统与不补气系统相比,制冷量增加了8%~20%,压缩机排气温度降低了1.30~4.50 ℃,系统制冷性能系数COP提高了5.8%~18.9%;在压缩机转速4 000 r/min时,低压补气系统排气温度均低于不补气系统,尤其在高温50.00 ℃环境下,低压补气系统排气温度为74.60℃,下降了6.25℃,制冷量增加了0.2%~6.1%,系统制冷性能系数COP提高了1.9%~14.4%。     

非共沸工质与纯工质在ORC系统中的特性比较研究

工质的特性是影响ORC(有机朗肯循环)系统性能的重要因素之一。建立了65~100℃低温地热水有机朗肯循环发电系统数学模型,将R245fa分别与R601a和R227ea以不同比例混合作为ORC系统的工质,比较了非共沸混合物和纯物质两类工质对ORC系统循环净功、热效率和火用效率的影响。研究结果表明:无论是纯工质还是非共沸工质,系统的循环净功、热效率和火用效率都随着热源温度的升高而增大。工质在相变过程中是否存在温度滑移,是影响ORC系统性能的重要因素之一。在65~100℃的热源条件下,综合考虑3个评价指标,当R245fa配比为0.1~0.7时,R245fa/R601a混合物的循环净功、热效率和火用效率分别提升0.012~2.48 k W、0.005%~1.15%和0.08%~10.7%;当R245fa配比为0.5~0.9时,R245fa/R227ea混合物的循环净功、热效率和火用效率分别提升0.049~4.25 k W、0.057%~1.75%和0.21%~16.1%。     

热管复合式机房空调系统节能研究

建立热管复合式机房空调系统的性能仿真软件,基于DeST气象数据,对哈尔滨、北京、上海、广州4个地区的空调能效进行对比分析,全年的制冷性能系数(EER)变化曲线均呈"U"型,室外平均气温越低,EER越高,节能性越好。与广州地区相比,上海、北京、哈尔滨机房空调系统的年度能效比(AEER)依次提高64%、105%、156%。基于北京地区的气象数据,分析空调系统变室温运行的能效特性,机房设定温度越高,EER越高,节能性越好。室内温度设定为33、30、27℃时的AEER相对24℃的依次提高56%、42%、19%。以节能减排为目标,热管复合式机房空调系统适宜应用在平均气温较低的地区,在满足电子设备可靠性的前提下,可适当提高机房的设定温度。     

高校教室夏季空调优化控制研究

为了分析不同的控制方案对高校夏季空调教室温度和能耗的影响,采用Trnsys软件对高校教室夏季空调系统进行了仿真研究。仿真研究分别针对作息控制、温度控制和人数控制三种方案,分析三种方案的温度和能耗进行对比研究。仿真模拟结果表明,三种方案中,人数控制方案的平均温度最为接近人体舒适的26℃,温度的均方差也最小。同时对三种方案的总能耗对比分析表明,人数控制方案的总能耗最低。因此可认为人数控制方案是高校教室空调系统最优控制方案。     

太阳能-地热能复合利用的溶液除湿空调系统研究

针对传统空调系统采用温湿度联合处理的方式而导致的舒适性差、能源消耗大等问题，以南昌市某建筑为研究对象，利用TRNSYS仿真软件建立太阳能-地热能复合利用的溶液除湿空调系统数学模型，并分析集热器面积及埋管数量对系统性能的影响，在此基础上选取合适的参数对系统全年运行工况进行模拟。同时针对夏季室外新风含湿量波动较大的问题，提出对新风采取分流处理的解决方式。结果表明：在制冷工况下，室内平均温度为26.1℃，相对湿度在50%～65%之间；在供暖工况下，室内平均温度为19.2℃，相对湿度大部分处于40%～60%之间，能够很好地控制室内热湿环境。供暖和制冷季节能效比分别为6.2和4.5，全年性能系数为4.7，明显高于传统的空调系统。     

重庆市酒店类建筑能耗调查及节能潜力分析

在对重庆市5家典型三星级以上酒店年用电量及空调系统运行调研的基础上,分析重庆市酒店类建筑的能耗特点,探讨空调系统及管理方面各分项节能潜力,为解决重庆市酒店类建筑能耗问题提供一些基础性数据。     

基于kmeans聚类与BP神经网络算法的办公建筑逐时电负荷预测

基于青岛某办公建筑2015年全年逐时总用电能耗及空调用电能耗数据,利用kmeans聚类算法对其进行聚类,将全年能耗水平分为四大类。利用求平均值法得到每一类典型设备使用率曲线。将典型曲线的数据、日前两周数据以及气象数据一同作为BP神经网络的输入,预测未来24小时的建筑总用电和空调用电,该方法比单用日前两周数据及气象数据进行负荷预测能获得更低的相对误差、均方根误差、平均绝对百分误差。BP负荷预测相对误差在5%以内,而kmeans-BP负荷预测算法控制在±2.5%以内;BP预测得到的均方根误差和平均绝对百分误差范围分别在4.6~9.0之间、2.3%~4.4%之间,kmeans-BP将该误差缩小到3.1、2.0%以内,对于负荷预测精度要求上是阶跃性的突破。     

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。     

高压变频器在炼铁厂节能改造中的应用

叙述了高压变频器系统的功能与节能效益,指出高压变频器应用于除尘系统的技术改造可提高设备的自动控制水平,还能达到节能降耗的目的。     

Energy economics of cooking in households in Nepal

This paper focuses on the economic analysis of energy consumed for cooking in urban households in Nepal. In this paper, annual energy requirements, energy efficiency, various combinations of fuels, stoves and utensils used for cooking and their corresponding costs have been examined through lab experiments and surveys. The estimate of system efficiencies for household cooking is one of the major contributions of this paper. The paper also discusses costs of energy use and compares various energy alternatives for cooking. It is believed that the analysis presented here will be helpful to the policy planners to devise better energy options for households.     

Condensation of vapor in the presence of non-condensable gas in condensers

This paper presents a set of differential and algebraic equations that model heat and mass transfer in condensers in which a mixture of water vapor and non-condensable gas is cooled. The model has been used to predict the condensation rate, the bulk temperatures of the coolant and the gas–vapor mixture, and the surface temperatures of the condenser wall. The predicted results for counter flow tube condensers are compared with three sets of published experimental data for system in which air is the non-condensable gas. It is found that the predicted condensation rates and coolant bulk temperatures agree very well with all the three sets of experimental data, the predicted wall temperatures agree reasonably well with the experimental results, and the agreement between the predictions and the experimental results on the bulk temperature of the air–vapor mixture is excellent for one set of the experimental data, reasonable for the second set of experimental data, but poor for the third set of experimental data. It is suggested that the poor agreement between the predicted and measured bulk temperatures of the mixture for the third set of experimental data arises from the experimental errors. The results from this study show that when modeling vapor condensation in the presence of a non-condensable gas, a simple model for the mixture channel alone may not be sufficient since neither the temperature nor the heat flux at the wall can be assumed to be constant. The results also show that the wall temperature in the coolant channel can be quite high, and careful modeling of the heat transfer in the coolant channel is needed in order to achieve good agreement between the model predictions and the experimental results.     

10月份煤炭市场供需形势综述

通过对我国10月份煤炭产量的分析,表明我国煤炭市场需求增势强劲,价格呈现了持续攀升的良好势头,同时指出受市场供需及其他因素的影响,近期煤炭价格还会上涨,煤炭供应和销售问题仍应引起有关方面重视。     

Utilization of straw in biomass energy in China

China is a big agricultural country and one of the most abundant straw resources in the world, producing more than 620 million tons of straw in 2002, and representing about 33–45% of energy consumption for livelihood in rural areas. Utilization of straw as energy with high efficiency and rationality not only meets the demands for energy as the economy grows, but also provide a basis for environmental protection and sustainable development of society in China. This paper reviews the present utilized technologies of straw in biomass energy, including improved stove, biogas, straw gasification and straw briquette, which are already commercialized and popularized in China. Other technologies, such as liquefaction, straw carbonization and bio-coal, are also presented. Based on the technology status and potential, the future research and development of straw in the biomass energy portfolio in China are proposed.     

Thermophoresis of particles in aqueous solution in micro-channel

A theoretical analysis of micro motion of particles under the action of thermophoresis in aqueous electrolyte solution is presented in this paper. A two-dimensional, incompressible and laminar fluid flow model is proposed to simulate the fluid flow and particle motion trajectory in micro-channel. The effects of thermophoretic force and viscous force on the particle are calculated. The particle trajectories considering the effects of particle size, inlet flow velocity and temperature difference between bottom side and top side in micro-channel with a length of 2000 μm and a height of 500 μm are simulated. The effect of thermophoresis on separation motion of particles in micro-channel is analyzed. The results show that thermophoretic force increases with the increase of temperature gradient in micro-channel and particles with smaller diameter, smaller density and smaller gravity acceleration can pass the micro-channel more easily.     

黏土矿物在电池领域的应用研究进展

黏土矿物是一类含水硅酸盐矿物,主要含铝、镁等元素,在我国储量丰富、价格低廉。基于其晶体结构、微观形态和物化特性,黏土矿物可用于制备电池材料,改善电池性能。本文简述了凹凸棒石(坡缕石)、海泡石、蒙脱石等黏土矿物在电池电解质、电极材料中的研究进展,对存在的问题进行了分析,为下一步的研究提出了建议。     

Cathodic electrodeposition of SnS in the presence of EDTA in aqueous media

Cathodic electrodeposition in the presence of EDTA in aqueous solution was found to offer some noteworthy improvements in our attempt to synthesise an SnS thin film. EDTA has shown its capacity for improving the longevity of the deposition bath as well as the adhesion of the deposited film on a titanium substrate. Photoelectrochemical analysis reveals outstanding photoactivity of the electrodeposited thin film, while an optical study shows an energy gap of approximately 1.1 eV. The effects of chelating agent were extracted from the results of cyclic voltammetry, photoelectrochemical test, scanning electron microscopy and X-ray diffraction spectroscopy. The latter which displays better defined signals reaffirms the appreciable improvement in the polycrystallinity of the thin film. Analysis of peak locations, coincidentally, confirms that SnS of Herzenbergite form has been obtained.