螺杆式水源热泵机组非标热力完善度规律的发现及其在水系统能耗模型中的应用

提出了"非标逆卡诺循环COP"和"非标热力完善度的概念",根据某品牌的螺杆式水源热泵COP修正参数表,计算同一负荷率下,变蒸发器出水温度、变冷凝器出水温度、变蒸发器相对流量、变冷凝器相对流量四种变工况条件下的"非标热力完善度",最大值和最小值误差为3.2%,通过其他型号和其他品牌的螺杆式水源热泵的COP修正参数的验证,发现同一负荷率下,螺杆式水源热泵机组的"非标热力完善度"基本不变的规律。该规律在水源热泵水系统能耗模型的建立中可以解决热泵机组能耗和源侧及用户侧水泵能耗的耦合问题,有较大的应用意义。     

一种新型热泵技术及其性能分析

本发明涉及一种热泵系统,自控系统正向控制时为双蒸发器热泵机组,它在制冷制热两种工况下始终有一换热器是蒸发器并处于制冷工况,而另外两个换热器则在不同季节分别承担蒸发器和冷凝器。自控系统反向控制时,本发明将成为一种双冷凝器热泵机组,在一个功能区间实现制冷或制热两种工况循环时,另一个功能区间可以一直实现制热工况。这两种情况均有利于热泵机组一机多用,提高设备利用效率。同时,对于双蒸发器系统,在冬季工况运行时,由于回收了排向室外的冷量,机组的综合COP值将大干传统的单蒸发器热泵机组,有利于节约能源：对于双冷凝器系统,机组在夏季运行时,由于回收了排向室外的热量,机组的COP值将大于传统的单蒸发器热泵机组,有利于节约能源。并且,不论在冬季工况下还是夏季工况下,由于本发明可以进行冷暖的同时供应,所以能够节省一套供暖或制冷设备,减少初投资。     

R417A热泵热水器性能及螺旋套管冷凝器换热研究

本文以R417A为工质,在冷凝器不同进水温度、不同进水体积流量时,测试了空气源热泵热水器的运行性能及螺旋套管冷凝器的换热特性,为制冷空调及热泵系统的工质替代提供参考。实验工况为:冷凝器入口水温20～55℃,冷凝器进水体积流量为0.6～1.0 m~3/h,环境温度分别为15、29℃。结果表明:冷凝器进水体积流量一定时,随入口水温的升高,冷凝器总换热量、总传热系数减小,压缩机排气压力、输入功率增大,热泵热水器制热量、制热性能系数COP下降。冷凝器入口水温一定时,随进水体积流量的增加,冷凝器总换热量、总传热系数增大,压缩机排气压力、输入功率减小,热泵热水器制热量、COP增大。实验工况范围内,与环境温度为15℃相比,环境温度为29℃时的冷凝器总换热量、总传热系数、排气压力、吸气压力、输入功率、制热量、COP均较高。     

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。     

城市原生污水源热泵机组的设计创新与实验研究

对现有城市原生污水源热泵机组当前的技术状况与存在的问题进行分析,并进行了改进,主要特色是:1)制冷剂侧切换污水源热泵系统;2)换热器采用蒸发、冷凝两用换热器;3)污水可直接进入换热器。同时,将变频螺杆压缩机及压缩机可变内容积比等重要技术应用到改进的机组中,并制作了污水源热泵机组样机。通过权威机构验证,污水源热泵机组处于名义制冷与制热工况下的满负荷运行性能卓越,产品优势明显。     

基于自然冷源蓄能供冷的冷藏陈列柜运行分析

本文采用TRNSYS软件建立自然冷源冷藏陈列柜系统仿真模型。选取陈列柜送风温度、载冷剂供冷温度为变量，以全年能耗作为考核指标对自然冷源食品冷藏陈列柜运行工况进行优化；在优化基础上分析系统运行特性，并与传统食品冷藏陈列柜能耗进行对比。结果表明：在冷藏陈列柜送风温度为-1.5℃,载冷剂供冷温度为-3℃时的优化工况下，系统年能耗最低，为11 506 kW·h,相比传统食品冷藏陈列柜系统能耗降低40.8%。优化工况下自然冷源蓄冷及供冷模式与自然冷源单独供冷模式总计运行时长为3 739 h,占全年总运行时间的42.7%。全年系统COP为3.9,制冷机组COP为4.1。     

具有防霜功能的低温型空气源热泵热水器性能研究

针对空气源热泵热水器在冬季低温环境下蒸发器容易结霜和机组效率降低的问题,提出一种具有防霜功能的低温型空气源热泵热水器,通过试验测试了热泵系统在不同低温工况下的性能。实验结果表明:通过在热泵系统蒸发器底部安装防霜换热器,可使热泵系统的输入功率平均提高了5.6%,制热量平均提高了9.3%,COP平均提高了5.5%,系统压缩机的排气温度明显降低。     

空气源热泵热水器系统性能分析

为了预测空气源热泵热水器的运行性能,提高系统稳定性和降低能耗,建立空气源热泵热水器系统仿真模型,在焓差实验室对一台水箱容积为150L的一体式空气源热泵热水器样机进行变工况实验以验证模型的准确性,利用所建立的模型研究蒸发器入口空气流速及制冷剂质量流量对机组性能的影响。结果表明:系统制热量和COP都随环境温度的升高而不断增大;系统制热量随蒸发器入口空气流速的增大而呈增大趋势,在达到某值后,系统制热量变化趋于稳定;系统COP随制冷剂质量流量的不断增加呈先增大后减小的趋势,即制冷剂质量流量存在最佳值使得热泵性能系数最高。     

严寒地区空气源热泵供暖运行性能研究

基于TRNSYS软件建立空气源热泵供暖系统仿真模型,模拟空气源热泵供暖运行性能,对比分析不同供水流量、不同月份以及3个典型供暖日下的系统COP。研究结果表明:室内温度及系统COP随室外温度的升高而升高,系统耗电量随室外温度的升高而降低;当室外温度恒定时,室内温度和系统耗电量随供水流量的增大而增大,但系统COP随供水流量的增大而降低;供暖期开始和结束时,空气源热泵运行性能稳定、满足供暖热舒适需求,供暖期室外温度最低时不宜单独使用空气源热泵。研究结果可为空气源热泵供暖系统在包头地区的应用提供指导。     

邯郸地区某空气源热泵供暖系统运行性能分析

为提高空气源热泵供热系统的实际运行性能,在2019—2020 年供暖季对邯郸地区某老旧小区空气源热泵供热系统进行了现场测试,根据室外空气温湿度、系统供回水温度及流量、耗电量的实测数据和变水温运行调节方式,对系统长期运行性能进行了分析,对比了4 种工况条件下的系统运行特性。测试分析结果表明：对于整个供暖期的能耗而言,分阶段变水温调节有利于促进空气源热泵节能运行。邯郸地区冬季室外相对湿度较高,容易导致空气源热泵运行效果不佳、供热量不足。此时在分阶段变水温调节的基础上采用分时段变水温调节,有利于改善系统运行效果,供暖期第Ⅱ阶段的COP′由1.63提高至第Ⅲ阶段的1.76,提高了8%。     

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.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

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.……     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.