寒冷地区空气源热泵与太阳能复合供热系统性能测试分析

根据典型用户供暖及热水使用需求,在寒冷地区搭建空气源热泵与太阳能复合供热试验系统,在供热季初中期进行运行测试研究。结果表明:复合供热系统可为北方寒冷地区典型家庭用户提供基本的供暖需求和生活热水使用需求,复合系统在满足2.5~3.6kW供暖负荷的同时,可提供280L以上不低于38℃的生活热水;蓄热水箱内温度对热泵单元的耗电量具有显著影响,且线性相关度较好,水箱平均温度与环境温度之差同热泵运行能效呈现较好的线性变化趋势,温差越大,热泵能效越低,运行中温差范围集中在30~40℃,期间热泵能效处于2.5~3.0;集热单元对于复合系统运行能效的提升也有一定程度的贡献,运行能效相对于热泵单元单独承担热负荷的工况可提升20%以上。     

多功能空气源热泵系统制热性能试验研究

为了对热泵型空调器进行冷凝热回收,提出一种新型多功能空气源热泵系统。对该系统在供热兼制热水模式下的性能进行试验分析。研究结果表明:在采取制热水优先策略的情况下,该系统平均COP为3.5;室内平均温度在20℃以上,达到冬季室内供热的温度标准。     

两种海水源热泵系统的性能测试及经济性分析

海水源热泵是直接或间接利用海水的能量进行冬季供暖、夏季供冷、全年热水供应的技术。文章分析了青岛地区采用直接热利用和间接热利用的两个工程实例,测试了两个热泵系统实际运行性能,并进行了节能性、技术性和经济性对比分析。根据测试及数据分析,与间接热利用系统相比,直接热利用的系统COP值高,初投资低,节能效益好,在采取措施保证热泵系统使用寿命的前提下,推荐采用直接热利用系统。     

一种采用R32的三联供系统

介绍一种带热水功能的R32热泵系统的专利技术及其实验研究与用户体验,该技术采用的制冷剂系统结构比传统的风冷热泵增加1个显热回收换热器,热水系统结构与传统的相比增加1个水路三通阀,其中热水箱含内置换热盘管,盘管内走循环加热水;能够实现单制冷、单制热供暖、制冷部分热回收、单制热水和制热同时制热水等5种运行模式;将R32排气温度高的缺点转化为优点,夏季可以得到75℃的热水,冬季可以得到85℃的热水,提高热水箱的使用效率。     

上海地区空气源热泵结合小温差换热风机盘管末端的供暖空调系统性能的实验研究

为解决夏热冬冷地区冬季供暖问题,本文设计了空气源热泵结合小温差换热风机盘管末端的分布式空调系统。实验研究表明:在冬季典型工况下采用35℃左右的热水供暖,系统制热性能系数(COP)可达3.0;在夏季典型工况下采用10℃左右的冷水制冷,系统制冷COP也在3.0以上。结果表明通过使用小温差换热末端降低了机组设定出水温度,改善了机组的运行工况,提升系统的能效比。系统解决了目前空气源热泵在冬季低温工况下供暖能效低、舒适性差等问题,为解决我国南方冬季供暖问题提供了可行方案。     

冷凝排热-相变蓄热热回收空调系统的实验研究

利用相变蓄热材料的相变过程将空调系统冷凝热回收并制取热水，解决空调系统运行时段与热水使用时段的时间差以及生活热水的用量与冷凝热量之间的不一致。针对冷凝排热相变蓄热热回收空调系统制备生活热水进行试验研究。实验结果表明，通过选择合适的相变蓄热材料，该系统试验工况下制取的热水达到了预期温度35～40℃，可满足洗浴用生活热水的温度要求；如需更高温度的热水，可在热水管路上设置辅助加热器加热，以满足要求。     

基于CFD的太阳能辅助地源热泵系统土壤热环境分析

针对地源热泵长期供暖工况运行引起的土壤冷堆积问题,采用太阳能集热面积与建筑冬季供暖热负荷之比k描述。理论与数值模拟结果表明:系数k可以作为合理选择太阳能集热面积的主要依据之一;给出以太阳能集热作为补热热源、改善土壤热环境的原理方法。以系统一年的补热与无补热运行工况为研究对象,采用CFD数值模拟方法,对太阳能辅助地源热泵联合供暖系统进行土壤热平衡分析。研究结果表明:在非供暖季节采用太阳能集热对土壤补热,是改善土壤热环境品质、提高地源热泵系统性能系数的有效方法之一。     

利用空气源热泵跨季节补热对单供暖地埋管地源热泵运行特性影响分析

针对大规模住宅小区单供暖地埋管地源热泵在实际运行中存在的问题,在对其运行现状进行分析的基础上,以其中一个项目为例,分析地埋管地源热泵在单供暖工况下长期运行时的土壤逐年温度变化和运行费用。指出应尽早抑制土壤温度进一步降低,使其稳定在较高水平,以保证系统持续可靠运行。提出以土壤年温度下降幅度为目标,利用空气源热泵跨季节补热解决土壤温度逐年下降的问题。研究结果表明,所计算项目从第5年开始补热,补热后每年供暖初期土壤温度为7.5℃左右,补热初投资为2.86元/米~2,补热费用为2.71元/米~2,供暖运行费用为9.35元/米~2,年运行费用为12.06元/米~2。     

太阳能辅助集热型水源热泵设计及特性分析

水-水源热泵机组在冬季温度较低的条件下运行一段时间后,会出现制热性能下降并频繁转入保护工况现象。为改善水-水源热泵性能,在负荷匹配的情况下提高其经济性,设想在原热泵系统中增设太阳能辅助集热装置。简要介绍太阳能辅助集热型热泵系统的形式和组成,包括太阳能集热器形式选择、贮热水槽的要求等,同时着重进行冬季供暖工况的热力设计计算。设计计算表明,冬季供热循环时增设太阳能辅助系统之后供热系数有较大提高。在夏季只需将太阳能集热系统与制冷系统分离,即可作生活热水系统使用。     

行为模式对户式空气源热泵地暖系统供热性能的影响

自主调节供水温度及开关部分供暖回路阀门等行为模式对户式空气源热泵地暖系统的节能与舒适性具有重要影响。本文以一实际住宅为例,实验研究了户式空气源热泵地暖系统在不同供水温度和改变供暖回路数量下的供暖特性,对室内空气温度、地面温度及系统耗电量等参数的实测与分析显示：室外平均温度为-2.3℃,按照机组最高供水温度55℃运行时,由于地面温度过高,地板表面温度局部不满意率超过20%,相对于供水温度30℃运行结果,耗电量增加191%,客厅与书房的温差增加2.5℃以上。室外平均温度为-1.7℃,关闭次卧和客卧相应的地暖回路阀门后,主卧、客厅和书房室温比全屋供暖时分别降低了1.4、2.9、0.5℃,系统耗电量降低18.7%。     

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 ...