回质回热过程对硅胶-水吸附机性能的影响及优化分析

在硅胶-水吸附机组中,采用水作为热管工质,这样使得热管工质和制冷工质一致,避免了不同工质而引起的渗漏问题。机组的加热/冷却切换是通过控制水路阀门来实现的,所以系统无需真空阀门。另外,在两个隔离器水盘间,安装了毛细管,这样可以避免单个吸附床缺水问题。对机组进行了回质和回热研究。回质过程可以有效提高系统的性能,进一步研究了热水进口温度对回质过程的影响。最后研究了回热对系统COP的影响,并讨论了回热过程的优化。研究表明:机组具有较好的吸附制冷性能,当热水进口温度/冷却水进口温度/冷水出口温度分别为79.2/29.6/14.9℃左右,回质时间为90s,回热时间30s,机组的制冷功率为15.3kW,性能系数(COP)为0.50;当热水进口温度/冷却水进口温度/冷水出口温度分别为64.8/29.6/15.2℃左右,回质时间为180s,回热时间30s,机组的制冷功率为7.5kW,COP为0.36。     

两级溴化锂吸收式制冷机的变工况性能实验

介绍了自主研制的350 kW两级溴化锂吸收式制冷机,并对该机组进行了4种变工况条件下的性能测试.分别通过改变冷媒水出口温度,冷却水进口温度,热水进口温度和热水流量来测试该制冷设备在以上4种常见变工况的外界条件下,其制冷量和热力系数(COP)的变化趋势.该实验结果显示,在设计值上下20％的变化范围内,随着冷媒水出口温度和热水进口温度的升高,热水流量的加大以及冷却水进口温度的降低,机组制冷量和热力系数(COP)均会得到提高.     

采用沸石-水工质对的吸附式制冷空调系统性能试验研究

介绍一种以沸石-水作为工质对的吸附式制冷空调系统,并对其热力性能进行试验研究。循环时间840s,驱动热源为80。c的热水,流量为2.80 m3/h;冷却水进口温度为25 °C ,供冷凝器冷却水的流量为2. 7 4 m3/h,供吸附床吸附时冷却水的流量为4.27 m3/h; 冷冻水进口温度为22。c , 流量为0. 71m3/ h。试验结果显示：机组在420~840s循环周期内,制冷量范围为1679~1905W ,系统C O P的范围为0.02~0.66。     

小型烟气-热水型溴化锂吸收式制冷机组试验研究

探究适合于匹配小型分布式能源的烟气-热水型溴化锂吸收式制冷机组可降低设备初投资及拓展应用场景,选取某国产130kW烟气-热水型吸收式溴化锂制冷机组为研究对象,通过搭建与之匹配的试验台,测试了该机组冷冻水出口温度和冷却水进口温度对制冷量的影响,并测试了余热烟气进出口温度和热水温度、冷冻水进出口温度、吸收机制冷量、高低发温度随时间的变化规律。研究结果表明,冷冻水出口温度每升高1℃,制冷量提升3-4%,冷却水进口温度每增加2℃,制冷量降低2-6%。烟气进吸收机温度在280-440℃之间变化,出口烟气温度维持在65℃。冷剂泵开启后（约吸收机启动20min）,高压和低发溶液出口温度随时间逐步升高,分别稳定在108℃和57℃,冷冻水进出口温度维持在15/10℃左右。吸收机制冷量维持在100-115k W。误差分析得到制冷量和冷冻水出口温度误差分别为8.6%和0.5%,显示了较高的准确度。     

低温排热吸收式制冷机的开发

本文介绍了日本开发的低温排热驱动吸收式制冷机 ,采用了两次提升的吸收式循环 ,并试制了 70k W制冷量的样机。试验结果 :在排热水进口温度 60℃ ,冷却水进口温度 2 5℃ ,冷媒水出口 7℃的工况下 ,实测制冷量达到 70 k W,制冷性能系数 (COP)达到 0 .5 8     

R245fa传热性能实验

蒸发器和冷凝器的传热性能是影响制冷机组和双工质发电机组做功效率的关键因素,为了提高中低温余热在热泵机组和地热双工质发电系统中的利用效率,本文选用R245fa循环工质,对满液式蒸发器和冷凝器进行实验研究,分别讨论热水温度进口温度对蒸发器和冷凝器的传热系数、蒸发压力和冷凝压力的影响。研究结果表明,在工质流量和冷却水流量保持不变的条件下,蒸发器传热系数随着热水进口温度和温差的增大而减小,冷凝器的传热系数随着热水进口温度的增加先增大后减小,蒸发器传热系数可以达到2500 W/(m2?℃);蒸发器压力和汽轮机前后的压差随着热水出口温度的增加而增加,热水流量对蒸发压力和冷凝压力的变化浮动较小。     

R245fa传热性能实验研究

蒸发器和冷凝器的传热性能是影响制冷机组和双工质发电机组做功效率的关键因素,为了提高中低温余热在热泵机组和地热双工质发电系统中的利用效率,本文选用R245fa循环工质,对满液式蒸发器和冷凝器进行实验研究,分别讨论热水温度进口温度对蒸发器和冷凝器的传热系数、蒸发压力和冷凝压力的影响。研究结果表明,在工质流量和冷却水流量保持不变的条件下,蒸发器传热系数随着热水进口温度和温差的增大而减小,冷凝器的传热系数随着热水进口温度的增加先增大后减小,蒸发器传热系数可以达到2500 W/(m2·℃);蒸发器压力和汽轮机前后的压差随着热水出口温度的增加而增加,热水流量对蒸发压力和冷凝压力的变化浮动较小。     

基于数据中心余热回收的硅胶-水吸附式制冷系统的实验研究

数据中心蕴含丰富的低温余热资源,若将硅胶-水吸附式制冷机组运用于数据中心余热回收且给水冷背板系统提供冷量满足服务器CPU直接水冷的要求及水冷背板的需求,将具有显著的节能效果。本文针对45～60℃的低温热源,对吸附式制冷机组进行实验,测量换热流体在不同工况下的温度,结果表明:硅胶-水吸附式制冷机组能够将23℃的冷冻水降温至20℃以下,产生1.28～4 kW的制冷量,系统COP在0.22～0.51之间。若提高热水温度,降低冷却水温度以及适度提高冷冻水温度可使硅胶-水吸附式制冷机组提供更多的冷量,节能效果更佳。     

低温热源驱动的二级吸附冷冻循环实验研究与性能分析

在冷冻应用方面,传统的吸附式制冷工质对在热源温度低于90℃、冷凝温度高于25℃的条件下,很难实现-10℃以下的冷冻。为了实现100℃以下的太阳能或废热利用,这里提出了二级吸附式制冷循环,建立了性能测试实验台。采用CaCl2-BaCl2-NH3作为工质对,利用85℃热源驱动,测试不同蒸发温度与冷凝温度下吸附剂的吸附与解吸性能。结果表明,二级吸附式制冷能够实现-20℃下的冷量输出,同时,冷却水温度为25℃时,氯化钙的循环吸附量、二级吸附式制冷COP与SCP分别为0.598kg/kg,0.24,106.6W/kg。     

动力电池液冷系统设计与试验研究

动力电池热管理对电池的运行效率、寿命、可靠性至关重要。基于客户要求设计一款额定制冷量及制热量分别约为7 kW和12 kW的热管理机组,并对其性能进行试验研究。结果表明:制冷量及COP随进水温度、进水流量的增大而增大,在压缩机转速为4 000 r/min时,制冷量最高可达9. 5 kW,COP最大可达2. 5;当环境温度在30℃以下时,COP随压缩机转速的增大先增大后减小,当环境温度在30℃以上时,COP随压缩机转速的增大而减小;系统的平均降温速率约为2℃/min;当PTC的设定功率大于6 kW时,PTC的实际功率与设定功率的误差在10%以内。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...     

Brainstorming for ISO Strategy 2016-2020

正Responding to ISO’s appeal for survey for the to-be-developed ISO Strategy Plan for 2016-2020,SAC hosted a special workshop over the needs and comments of various fi elds on June 8 in Beijing.The workshop was attended by ISO President-elect and Ansteel General Manager Zhang Xiaogang,SAC Vice-Administrator Yu Xinli,and 30 experts from     

CNAS Passes APLAC's PTP Review

正The review group of Asia Pacific Laboratory Accreditation Cooperation(APLAC)carried out a 4-day peer review of the proficiency testing provider(PTP)for China National Accreditation Service for Conformity Assessment(CNAS)from July 28 to 31,2014.CNAS passed the PTP review with excellent performance.Two senior peer reviewers of APLAC made a comprehensive,rigorous and detailed review of CNAS’s PTP accreditation activities,and made the on-spot inspection of the review groups in Shanghai and Shenzhen respectively.