采用变回水温度控制策略的空气源热泵空调系统研究

为了提高空气源热泵空调系统运行性能,研究了一套采用变回水温度控制策略的空气源热泵机组的制冷性能。实验研究表明,变回水温度工况可满足室内冷负荷需求。与传统采用定12℃回水温度的空气源热泵空调系统相比,COP更高,耗电量更小,是一种高效节能的空气源热泵空调系统控制方法。此外,所建立的Dymola模型从理论上验证了实验结果,在此基础上模拟实际空调系统的能耗,模拟结果表明,COP由3.99提高至4.39,提高了10%。     

某办公楼地源热泵空调系统设计与总结

在上海及其周边地区，建筑物夏季空调冷负荷大于冬季热负荷，地源热泵埋管的区域存在热积累，出现严重的冷热负荷失衡，导致土壤温度逐年升高，影响系统长期运行效能。采用辅助冷却复合地源热泵系统，能很好地解决土壤热平衡问题，同时也可有效降低系统（地下埋管）投资，提高系统的运行节能效果。夏季普通冷负荷时，完全依靠地源热泵供冷；夏季冷负荷较大时，即空调主机冷凝出水温度达到37℃时启用辅助冷却装置，使辅助冷却装置和地源热泵机组联合运行。     

上海地区风冷-地源热泵复合系统经济性分析

由于控制逻辑简单,近年来风冷-地源热泵复合系统越来越多地受到关注。为分析风冷-地源热泵复合系统的经济性,本文以上海地区某小型空调系统为例,在系统全寿命期内采用费用现值和费用年值的方法,比较风冷-地源热泵复合系统、地源热泵系统、冷却塔复合式地源热泵系统、空气源热泵系统这4种类型系统经济性的差异。计算得到,4种空调系统的费用现值分别为64.14万元,67.96万元、65.77万元和64.79万元;4种空调系统的费用年值分别为8.43万元、8.94万元、8.64万元和8.52万元。结果表明,在这4种空调系统中,风冷-地源热泵复合系统的动态经济特性最优,具有较高的应用及推广价值。     

地源热泵空调系统设计实例分析

以烟台地区某公共建筑为例,借助HDY-SMAD全年动态负荷模拟软件对建筑物的冷热负荷进行模拟计算,根据全年能耗分布曲线图、季节性能耗分布曲线图和全年负荷频率分布图进行冷热源的匹配,并从室外土壤换热系统及室内空调通风系统两方面对地源热泵空调系统进行了全面介绍;最后通过经济性比较,说明了地源热泵空调系统在节能环保方面的优势.     

地源热泵复合系统在鄂州市民中心的应用

通过对鄂州市民中心空调系统的研究,详细介绍基于地源热泵机组+冷水机组的复合系统的设计思路,从系统投资及节能方面讨论公共建筑采用地源热泵复合系统进行清洁供暖的优劣性。结果表明:地源热泵复合系统冬季能效比可达3.42,每年减少碳排放454 t,投资回收期小于5年。本项目为地源热泵复合系统在公共建筑中的应用和推广提供参考。     

基于运行数据的地源热泵系统性能分析

建筑全年冷热负荷特性对地源热泵空调系统逐年供冷供热能力和地源侧的热平衡有直接影响.以贵阳某综合医院地源热泵空调系统2015-2019年连续监测为期4年的数据为基础,通过计算该地源热泵系统制冷季、制热季的平均部分负荷率、热泵主机的COP和EER,分析了冬、夏季地源侧和用户侧的供回水温度变化,介绍了该地源热泵系统夏季制冷、...     

地源热泵空调系统的设计

分析了地源热泵系统的特点 ,对地源热泵空调系统设计过程中经常遇到的冷热负荷确定、地热换热器的选型、室内空气的气流组织形式、热泵的容量等问题进行探讨     

办公楼变频空气源热泵序列优化控制

为了满足公共建筑中空调系统部分负荷下的节能运行调节需求,制冷机房经常配置多台冷水机组。空调系统中冷水机组能耗占比较高,而机组序列控制在系统满足室内负荷需求与节能中运行起关键作用。为了提高热泵机组的运行能效,本文提出一种空气源热泵机组的序列优化控制方法。首先建立变频空气源热泵机组模型,然后建立多台同型号机组序列优化控制目标函数,同时给出实时建筑负荷下求解机组最佳运行序列组合的算法与步骤。以某工程为例,利用e QUEST软件分析了办公楼全年的空调负荷变化,并在夏季、冬季典型日负荷基础上,对比分析了热泵机组序列优化控制策略与传统策略。结果表明:与传统策略相比,在10%~100%的系统部分负荷范围内,采用序列优化控制策略的机组能耗平均降低13.4%。在夏季典型日,热泵机组能耗降低14.5%;在冬季典型日,热泵机组能耗降低12.3%;在过渡季典型日,热泵机组能耗降低3.3%。在供冷季,采用机组序列优化控制策略能耗降低14.1%;在供热季能耗降低9.0%。热泵机组的序列优化控制策略具有明显的节能效果。     

复合式地源热泵系统的回顾与发展

在冷负荷占优地区,采用冷却塔辅助地源热泵系统(复合地源热泵系统)可以有效地缓解单一地源热泵系统长期运行所带来的土壤温升问题,目前研究较多。首先回顾了地下埋管换热器的理论模型,并对常用的六种模拟软件进行了比较。综合复合式地源热泵系统的国内外的研究现状,重点对复合地源热泵系统的运行策略进行了对比分析,并提出了新的设想,以期对复合式地源热泵系统的合理应用和科学发展提供支持。     

地埋管地源热泵复合蓄能系统方案可行性分析

根据办公楼所在的武汉地区气候特点及水文地质状况,在满足建筑物房间供冷供热要求的同时,采用地埋管地源热泵蓄能复合式空调系统,并利用消防水池作为水蓄冷装置。采用蓄冷优先的控制策略,能充分利用谷段电力,由蓄冷量满足尽可能多的冷负荷,不足部分由冷水机组直接供冷,可提高空调系统的运行效率,降低运行费用。经过方案的对比分析表明,该办公楼实施地埋管地源热泵中央空调蓄冷(热)项目,虽增加了投资成本,比常规空调系统在每年运行费用却可节约34.75万元,节能效率为78.6%,节能效果好,6年左右可收回高出的初投资。因而,从经济和技术的角度来说,该办公楼应用地埋管地源热泵复合式系统是可行的,运行费用低,社会经济效益显著,符合国家节能减排和可持续发展政策。     

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.……     

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...     

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.     

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.     

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.     

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