如何使多联机空调系统更加节能

介绍了多联机空调系统及其特点，并进行了节能分析。为了使多联机空调系统更加节能，提出了系统设计时应注意的要点。     

建筑节能与变冷媒流量多联机空调系统的适用性

分析了变冷媒流量多联机空调系统的特点，结合实际工程进行了论证，指出变冷媒流量多联机空调系统适用性的关键在于建筑本身的使用功能，而与建筑规模并无直接的关系。在大型公共建筑中，只要合理选用、正确设计，变冷媒流量多联机空调系统在建筑节能中可以起到非常重要的作用。     

数码多联中央空调节能术分析

指出数码多联机是中央空调的一个很有潜力的发展方向，分析数码多联机在节能技术方面采用的主要技术，即数码变容涡旋压缩机技术、双压缩机技术、制冷剂直接输送技术、制冷剂的智能分配技术、风机调速技术等多项节能技术。指出了进一步研究和推广数码多联机需要解决问题。     

变容量多联机压缩机技术路线

介绍变容量多联机压缩机的四种技术路线及特点，对其中三种路线在多联机系统中的应用进行对比，并对我国多联机市场做出预测。     

关于冷媒变流量多联机空调系统设计的探讨

根据多联机空调系统的特性,分析了配管长度对多联机空调系统制冷量和能效比的影响;提出了合理使用多联机、提高空调系统制冷量和能效比的建议。     

多联机维修软件的应用与分析

从维修角度出发,系统介绍了三菱重工多联机的基本控制原理和多联机维修软件MentePC的基本功能;结合实际案例分析了多联机的故障原因,并提出了解决方法和维修技术要点。     

多联式空调(热泵)机组APF能效标准分析

对多联式空调(热泵)机组(简称"多联机")施行的能效标准进行对比分析。依据多联机市场分布区域数据,选取3个区域中心城市:上海、广州和北京,根据厂家提供的部分负荷性能数据,分别计算多联机的APF(SEER),并与标准规定值、厂家实际标称值做了对比分析。结果表明:多联机制热性能极大影响APF,当前标准规定的多联机能效值偏低,不能有效推进多联机技术进步。以北京为例,8hp多联机计算APF比现行标准规定值高约57%,16hp多联机计算APF比现行标准规定值高约28.5%。基于分析结果,针对多联机能效标准的后续改进提出建议。     

多联机经济寿命期后节能改造研究

多联机中央空调占据市场容量的半壁江山，但是在长期运行过程中不可避免的出现能效下降、制冷制热效果差、噪音大等问题，传统的多联机更新会产生大量的废旧管道、影响用户日常生活、破坏装修等。为此，本文提出，从冷媒管路系统维护设备的研制出发，通过设备结构设计和控制设计，以期达到多联机经济寿命期后节能改造的目的。     

R22和R410A多联机配管长度理论分析

随着多联机的广泛使用,多联机配管长度对机组性能的影响一直是业内关注的问题.配管长度的增加,虽然可以扩大多联机的作用域,但是同样带来了回油困难、制冷量衰减和系统需允注大量制冷剂的问题.这就造成多联机从理论上具有节能潜力,而实际使用中则未必.就机组配管长度对机组的影响进行了理论分析计算,讨论了多联机的经济配管长度.     

变频多联机回油问题探讨

本文先提出了变频多联机中的回油问题，然后分析了制冷、制热时各段管路的制冷剂状态以及该状态下的回油情况，并且给出了变频多联机运行中回油措施。接着文章讨论了其他一些影响回油的因素。     

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.……     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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 ...