基于IPLV的冷水机组性能探讨

阐述IPLV在AHRI550／590不同版本中的修订,分析IPLV在GB50189—2005和GB／T18430．1—2007中的定义与区别。明确指出JPLV的用途及适用范围,最后基于IPLV分析多台冷水机组整体性能的优化,即利用建筑空调冷负荷时间频数和冷水机组部分负荷性能系数及机组群控策略进行多台冷水机组的性能优化。     

工业用冷水机组设计选型中性能评定的讨论

通过对比分析国标GB/T18430.1和美标AHRI 550/590,认为前者不适合对工业用途冷水机组进行有效的性能评定。因此,一个简单的方法被提出来,以计算工业用冷水机组部分负荷的平均性能系数来作为设计选型的参考依据。     

多联式空调（热泵）机组能效的理论极限

分析多联式空调（热泵）机组的换热器热平衡,推导其综合性能系数极限值的计算方法,并用该计算方法计算得知,在GB/T18837—2002规定的工况下,多联机IPLV（C）的极限值为18.19,IPLV（H）的极限值为10.35。指出若不能通过改进盘管设计、增大换热面积、提高盘管换热效率的方法使满负荷下的室内盘管空气温差和室外盘管空气温差分别低于8℃和10℃,多联机的综合性能系数将很难突破以上极限。     

允差范围对水冷式冷水机组性能测试的影响

分析允差在国家标准GB/T18430.1—2007规定范围内变动对水冷式冷水机组性能测试的影响,研究发现:基于GB/T18430.1—2007的允差范围,会导致对水冷式冷水机组制冷量的不合理判定;同时,基于现有允差范围,还会弱化水侧污垢系数修正温差对IPLV测试工况的影响。研究成果能够为准确测定水冷式冷水机组的性能、冷水机组国家标准和能效标准的修订提供参考,也为设计高精度的试验台提供理论参考。     

基于IPLV权重系数算法对冷水机组选型的探讨

通过对ARI550/590中IPLV权重系数的计算方法及对冷水机组部分负荷运行性能的介绍分析,提出了冷水机房IPLV的概念,并由此提出对冷水机组选型的讨论.     

基于HFO的混合制冷剂R514A在离心式冷水机组中直接替代R123制冷剂的试验研究

R514A是一种低GWP,不可燃、基于HFO-1336mzz(Z)的新一代制冷剂,其物性参数与R123接近。因此,本文选择R514A作为原R123离心式冷水机组的替代制冷剂开展试验研究。依据GB/T18430.1—2007规定的试验工况,针对直接充注R514A和原制冷剂R123的机组性能进行测试,对比研究R123和R514A在离心式冷水机组中的机组输入功率、制冷量、性能系数(COP)、压缩机吸/排气压力、压缩机排气温度,并计算综合部分负荷性能系数(IPLV)值。结果表明:在对原机组结构不做任何改动,仅更换机组润滑油的情况下,R514A机组与原R123机组相比压缩机吸/排气压力和排气温度较为接近,COP和IPLV性能略有提升。     

冷水机组综合部分负荷性能系数(IPLV)测试方法解析

新版的GB 19577-2015《冷水机组能效限定值及能效等级》标准已于2017年1月1日正式实施,新版标准在2004版的基础上做了较大程度的修改,冷水机组的能效考核指标由冷水机组名义工况下的性能系数COP,修改为冷水机组的性能系数COP和综合部分负荷性能系数IPLV。本文通过对测试标准、工况、污垢系数计算、机组的卸载逻辑等方面的解析,阐述了冷水机组综合部分负荷性能系数IPLV测试的环节和方法,以供业内试验室同行参考。     

AHRI冷水机组认证简析

为了方便广大冷水机组厂商全面地了解AHRI冷水机组认证的相关情况,本文对AHRI冷水机组认证的范围、参照标准AHRI 550/590和AHRI 551/591及标准的更新内容、认证模式等方面分别作了介绍。     

GB 19577—2015《冷水机组能效限定值及能效等级》标准解读

本文主要介绍了冷水机组能效标准GB19577—2015中冷水机组的能效限定值和能效等级的变化点。GB19577—2015能效等级依据冷水机组性能系数(COP)和综合部分负荷性能系数(IPLV)两项指标进行划分,并且能效等级从原来的5级变为3级。通过与国际上冷水机组能效标准的比较分析,指出GB19577—2015与国际上发达国家的能效标准存在一定差距。     

水冷冷水机组IPLV试验方法的探讨

阐述了依据国家标准GB/T18430.1-2007检测水冷冷水机组IPLV数值的目的和意义,着眼于水冷冷水机组性能试验方法基本原理,对检测过程中的误区和影响因素进行分析,为保证测量准确性提供参考。     

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 ...     

Effect of Oxide Assisted Metal Nanoparticles on Microstructure and Morphology of Gallium oxide Nanowires

Several researches have been reported about the characteristic of β-Ga2O3 nanowires which was synthesized on nickel oxide particle. But indeed, recent researches about synthesis of β-Ga2O3 nanowires on oxide-assisted transition metal are limited to nickel or cobalt oxide catalyst. In this work, Gallium oxide (β-Ga2O3 ) nanowires were synthesized by a simple thermal evaporation method from gallium powder in the range of 700 - 1000℃ using the iron, nickel, copper, cobalt and zinc oxide as a catalyst, respectively. The β-Ga2O3 nanowires with single crystalline without defects were successfully synthesized at the reaction temperature of 850, 900 and 950℃ in all the catalysts. But optimum experimental condition in synthesis of nanowires varied with the kind of catalyst. As increasing synthesis temperature,the morphology of gallium oxide nanowires changed from nanowires to nanorods, and its diameter increased. From these results, we could be proposed that the growth mechanism of β-Ga2O3 nanowires was changed with synthesis temperature of nanowires. Microstructure and morphology of Synthesized nanowire was characterized by HR-TEM, FE-SEM, EDX and XRD.     

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