房间空调器能效分析

简要介绍GB12021.3—2010对房间空调器产品的能效要求,并对国家压缩机制冷设备质量监督检验中心测试所得的部分分体式房间空调器能效比数据进行统计分析。结果表明,未达到产品能效限定值的产品占检测产品的3%;额定能效等级越低,产品合格率越高;存在个别企业产品能效比虚标现象。     

The erosion energy efficiency of sputtering

A new parameter of sputtering, the erosion energy efficiency, is defined as the ratio of the theoretical energy required to eject atoms to the experimental energy. This efficiency η (E) is shown to be proportional to the ratio of the sputtering yield Y(E) to the energy E and, even under optimum conditions never exceeds ～ 10%. The relationship of this efficiency to the broadening process occurring during sputter profiling resulting from recoil atomic motion and mixing is examined. It is shown that the ion energy conditions employed in both technological etching and sputter profiling systems are near optimum for energy utilization and profile broadening minimization.     

Efficiency of pulse high-current generator energy transfer into plasma liner energy

The efficiency of capacitor-bank energy transfer from a high-current pulse generator into kinetic energy of a plasma liner has been analyzed. The analysis was performed using a model including the circuit equations and equations of the cylindrical shell motion. High efficiency of the energy transfer into kinetic energy of the liner is shown to be achieved only by a low-inductance generator. We considered an “ideal” liner load in which the load current is close to zero in the final of the shell compression. This load provides a high (up to 80%) efficiency of energy transfer and higher stability when compressing the liner.     

东南亚地区房间空调器能效标准解析

通过对东南亚地区房间空调器能效标准及其发展趋势的分析,发现东南亚地区房间空调器的测试标准和能效标准正处于升级阶段。各国能效测试标准主要参考国际标准ISO 16358-1:2013,并且根据各自地域气候条件相应调整与修订能效标准。研究结果有利于我国房间空调器出口产品平台的开发和模块化设计,提高产品开发效率。     

Modelling and analysis of energy footprint of manufacturing systems

Increasing the energy efficiency of manufacturing plants will reduce the production costs and environmental impact. In order to analyse and improve the energy efficiency of manufacturing plants, however, we need models to evaluate the energy footprints of the plants. A key challenge of estimating plant-level footprints is that systemic methods of connecting information on the product, machine and plant levels are not available. Thus, we propose methods to parameterise product-level elements and to model machine-level factors based on those elements. From the machine-level models, the proposed approach performs simulation experiments and provides the energy footprints in closed-form equations for the plant level. We also suggest that the resulting model can be combined with probabilistic techniques to benchmark the energy efficiency of plants at the industry level. In a case study, we demonstrate how to apply the proposed methods to estimate the energy footprint of a hypothetical plant. The procedures introduced here enable manufacturers to evaluate the energy consumption of their facilities at early stages of manufacturing, and provide tools to assess the energy efficiency of their plant by comparison with peers.     

Pyroelectric energy conversion: optimization principles

In the framework of microgenerators, we present in this paper the key points for energy harvesting from temperature using ferroelectric materials. Thermoelectric devices profit from temperature spatial gradients, whereas ferroelectric materials require temporal fluctuation of temperature, thus leading to different applications targets. Ferroelectric materials may harvest perfectly the available thermal energy whatever the materials properties (limited by Carnot conversion efficiency) whereas thermoelectric material's efficiency is limited by materials properties (ZT figure of merit). However, it is shown that the necessary electric fields for Carnot cycles are far beyond the breakdown limit of bulk ferroelectric materials. Thin films may be an excellent solution for rising up to ultra-high electric fields and outstanding efficiency. Different thermodynamic cycles are presented in the paper: principles, advantages, and drawbacks. Using the Carnot cycle, the harvested energy would be independent of materials properties. However, using more realistic cycles, the energy conversion effectiveness remains dependent on the materials properties as discussed in the paper. A particular coupling factor is defined to quantify and check the effectiveness of pyroelectric energy harvesting. It is defined similarly to an electromechanical coupling factor as k2=p2theta0/(epsilontheta33cE), where p, theta0, epsilontheta33, cE are pyroelectric coefficient, maximum working temperature, dielectric permittivity, and specific heat, respectively. The importance of the electrothermal coupling factor is shown and discussed as an energy harvesting figure of merit. It gives the effectiveness of all techniques of energy harvesting (except the Carnot cycle). It is finally shown that we could reach very high efficiency using 1110.75Pb(Mg1/3Nb2/3)-0.25PbTiO3 single crystals and synchronized switch harvesting on inductor (almost 50% of Carnot efficiency). Finally, practical implementation key points of pyroelectric energy harvesting are presented showing that the different thermodynamic cycles are feasible and potentially effective, even compared to thermoelectric devices.     

空调系统能效指标探讨

针对目前空调系统中各种能效指标表示符号不一致的现象,分析能效比理论极限,并对各种能效指标进行比较,进而使不同能效指标的概念及应用逐渐清晰化。     

Design of rural energy systems

Current focus on rural energy has resulted in the emergence of numerous strategies and a variety of technologies employing different-conversion processes and sources. This paper suggests a methodology for finding out the overall first law system efficiency for various routes of energy supply. The method is not an optimisation technique but gives clues regarding the choice of energy sources for maximum overall efficiency of the system. Results indicate that a decentralised system with multi-energy sources is the most efficient (efficiency 12%) for villages.     

我国制冷空调产品能效标识制度实施概况

能效标识制度作为能效标准的实施和延伸,以其投入少、见效快、对消费者影响大、节能与环保效果显著的优点,成为世界各国普遍采取的一项节能管理措施。制冷空调产品属于典型的使用量大、应用面广、节能潜力和技术提升空间大的用能产品,对其实行能效标识管理意义重大,效果显著。本文重点介绍我国5类制冷空调产品能效标识制度实施情况,并简要介绍国外部分国家能效标识实施情况,旨在借鉴成功经验,推动我国能效标识制度取得更大进展。     

提高家用空调器能效比的分析探讨

节能减排已经成为我国经济可持续发展的重要任务,研发和推广高能效比的空调器可有效提高能源利用率。新出台的国家能效标准规定,从2009年开始,我国家用分体壁挂式空调器的能效比最低标准将从原来的2.6提高到3.2,提高空调器的能效水平成为当前空调行业的焦点。本文通过采用高效压缩机、提高换热器效率、翅片的高效化、高效换热技术如亲水膜、内缧纹铜管、提高室内外风扇的性能、合理选取制冷剂的分路数、毛细管长度和充灌量的优化匹配等措施,提高空调器的能效比从而实现节能的目的。     

电梯能效实时记录仪及系统研制

针对目前电梯能效监测方法繁杂、工作效率低及在模拟工况下不能完全反映电梯能效等问题,研制一套可在电梯实际运行工况下实时监测电梯能效记录仪及系统。该系统采用电力仪表与电流互感器测量电梯电参数,利用霍尔开关传感器测量电梯运动参数,基于双核ARM架构,应用有限状态机方法设计人机交互系统,选用SD卡存储实时能效数据;结合GSM模块,实现电梯能效信息短信查询、系统故障报警功能。测试结果表明:系统工作稳定,各项指标到达设计要求,具有推广价值。     

Experimental assessment of energy storage via variable speed compressor

In this study, usage of a variable speed refrigeration system in latent heat thermal energy storage (LHTES) system is investigated to increase energy storage efficiency. Four different compressor speed control cases are compared to obtain a constant heat transfer fluid (HTF) temperature at the inlet of the energy storage tank. These control cases are (i) control with evaporation temperature, (ii) control with ethylene glycol temperature at the outlet section of evaporator, (iii) control with suction pressure of the compressor and (iv) on/off control. By means of the experimental analysis the best control strategy is obtained as control with Case (ii), in terms of stability of inlet temperature of heat transfer fluid, variations of energy efficiency of LHTES and coefficient of performance (COP) of the system. While the Case (ii) provides the most stabile inlet temperature of HTF, Case (iv) represents the worst stability. Besides, the highest energy efficiency (99.0%), exergy efficiency (87.0%) and COP (2.05) values observed in Case (ii). Additionally, the time period to reach the set value is nearly 50 min in Case (i), Case (iii) and Case (iv) on the other hand this unstable initial time period becomes nearly 25 min for Case (ii). As a result, variable speed compressor should be controlled with Case (ii) to stabilize ethylene glycol-water solution temperatures as well as increase efficiency and COP of the system.     

蒸发式冷凝器能量调节分析和节能运行应用

通过对蒸发式冷凝器热工性能影响因素的分析,给出分别适用于空气流量、喷淋水量、喷淋水温和换热面积变化的不同能量调节方式和节能运行的应用。由数据分析可知,改变风量的能量调节方法最灵活,节能效果最佳,调节范围最广,值得推荐广泛采用。北方低温偏冷地区建议冬季采用干工况运转,不仅能够省去喷淋水泵的能耗,而且能够降低结冰的危害。并给出简单易行的可独立控制的盘管组加工方法。总之,通过多种调节方式组合,可以拓宽能量调节范围,优化系统组合,提高节能效果。     

Modeling the relaxed cohesive energy of metallic nanoclusters

A model is developed to calculate the cohesive energy of metallic nanoclusters with relaxed structure. It is found that the relaxed cohesive energy is higher than that of the un-relaxed one due to relaxation process decreasing the total energy. The relaxed nanoclusters in present model are more close to real ones, and the efficiency of the model is confirmed by molecular dynamics results on Cu nanoclusters.     

Green energy?

The UK gets nearly all its energy from the fossil fuels (coal, oil, gas etc.) and nuclear power, approximately 15% being consumed in the form of electricity. It is now well known that the burning of fossil fuels is accompanied by atmospheric pollution in the form of acid rain, ozone depletion and the greenhouse effect. Renewable energy sources, e.g. wind, solar, tidal, wave, hydroelectric and geothermal power do not at present contribute significantly to the UK energy supply and are also accompanied by adverse effects on the environment. The best hope for meeting future energy needs may lie in containing energy consumption, increased generation efficiency and an expanded nuclear power programme. The author discusses the problems of acid rain and the greenhouse effect and describes several forms of renewable energy: wind energy, solar energy, tidal power, wave power, hydroelectricity, biomass geothermal power and nuclear power     

Design of balanced energy savings performance contracts

Energy savings performance contracts between the energy users and the energy service companies (ESCO) are used to finance energy efficiency investments by using the future energy savings that will result from these investments. We present an analytical model to characterise the energy savings performance contracts and discuss how the risks of estimating the energy savings affect the energy user and the service provider. This characterisation allows determination of the contract parameters for a balanced contract with the information about the energy savings that are expected from the planned energy-efficiency investments. Since it is difficult to get the statistical information about the energy savings before investing in an energy-efficiency project, we develop a distribution-free contract that sets the guaranteed energy savings level based on the mean and the standard deviation of the energy savings and the profit-sharing ratio between the ESCO and the energy user. We show that a simple distribution-free balanced contract performs satisfactorily when the distribution of the energy savings is not known and its mean and the standard deviation are estimated with error. Our analytical results show that the energy savings contracts with the right parameters can mitigate the risks related to realisation of the anticipated energy savings.     

Electrokinetic energy conversion efficiency in nanofluidic channels

We theoretically evaluate the prospect of using electrokinetic phenomena to convert hydrostatic energy to electrical power. An expression is derived for the energy conversion efficiency of a two-terminal fluidic device in terms of its linear electrokinetic response properties. For a slitlike nanochannel of constant surface charge density, we predict that the maximum energy conversion efficiency occurs at low salt concentrations. An analytic expression for the regime of strong double-layer overlap reveals that the efficiency depends only on the ratio of the channel height to the Gouy-Chapman length, and the product of the viscosity and the counterion mobility. We estimate that an electrokinetic energy conversion device could achieve a maximum efficiency of 12% for simple monovalent ions in aqueous solution.     

面向企业能效评估的能源消耗过程建模方法研究

针对企业能效评估对能源消耗系统模型的需求,在分析企业能耗过程的组成因素及其相互作用关系的基础上,提出了一种将企业的生产过程、物料移动、资源配置、余能回收利用等数字化的,基于模糊高级Petri网的企业能源消耗过程建模方法,并详细地给出了模型的形式化定义、运行规则以及建模原则.实例分析表明,该方法独立于特定的能源类型和用能设备,实现了能耗过程结构和动态行为方面信息的全面描述,是企业能源消耗过程分析与优化的基础.     

医用内窥镜光能传递效率的评价方法

建立医用硬性内窥镜光能传递效率的评价方法.通过影响光能传递效率的原因分析并结合光能传递效率的实际应用意义,提出了有效光度率定义和表达式,以表示医用硬性内窥镜的光能传递效率.运用光度学原理导出有效光度率测量的应用公式,并通过对相关的模拟视场面与光度量关系的理论推导,得出有效光度率测量的应用公式与模拟视场形状无关的结果,并进一步采用几个典型视场面下的实际测量,验证了该应用公式的通用性.此方法可用于医用硬性内窥镜光能传递效率的评价,便于实际测量应用.     

中央空调节能措施研究

近年来随着社会经济的持续快速发展,我国建筑行业呈现出蓬勃发展的态势。与此同时,中央空调系统的应用日益普及,由此造成的能源消耗已成为影响国家能源战略的重要方面。因此,研究节约能源、提高能效的技术手段和方法迫在眉睫。文章根据实际经验,从中央空调的维护结构、冷热源、系统设计及运行方面研究并分析了促使中央空调系统节能运行,提高能源利用率的各种措施。