小型太阳能气泡泵吸收式制冷机研究

本文确定了设计计算参数下小型太阳能气泡泵吸收式制冷机制冷循环中各状态点参数,进行了发生器、冷凝器、蒸发器、吸收器、溶液热交换器的热负荷计算和加热热水、冷水、冷却水、稀溶液等循环介质的流量计算.进行了发生器、冷凝器、蒸发器、吸收器、溶液热交换器等换热设备所需的传热面积计算.根据求得的传热面积确定了各换热设备的传热管数,计算了热水进出口配管、冷却水进口配管、冷媒水进口配管的内径尺寸,为开发小型吸收式制冷机提供了一定的理论和实践基础.     

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。     

干冰除垢技术在油田加热炉除垢工作中的应用

加热炉是一种将燃料燃烧产生的热量传给被加热介质而使其温度升高的加热设备。就目前加热炉使用状况，实际热效率与设计相差较大。主要是由于结垢和杂质沉积，造成传热不良，据有关资料介绍，受热面每增加1mm的垢，将多消耗燃料1％～2％。本文在分析当前油田加热炉除垢工作的同时，提出将新型的干冰喷射除垢技术应用于油田加热炉除垢工作的设想和可行性分析，并对该技术的应用前景作出了展望。     

多功能热泵空调与热水负荷调节的理论分析与试验研究

为了解决多功能热泵空调兼制热水工况时热泵的能量输出与热水负荷和空调负荷之间的平衡问题,就必须根据空调或热水的负荷的变化对热水换热量和空调换热量进行能量调节.首先,对现有的几种能量调节方式进行了分析,针对各自的优缺点,提出了一种新的变流量调节方式,并进行了理论可行性分析;然后进行试验研究,实验结果表明,增加热水换热器循环水流量能加大热水换热量、减少空调换热量;降低热水换热器循环水流量能减少热水换热量、加大空调换热量.因此,可采用以满足空调负荷为控制目标,通过变热水换热器循环水流量的方式对热水和空调的热量分配进行动态调节.     

真空条件下除湿溶液再生的模拟与实验研究

除湿溶液的高效再生是除湿空调系统运行的重要保障。为研究除湿溶液的再生效率,将真空技术应用于溶液的再生过程,搭建了真空条件下的除湿溶液再生试验台。真空再生罐由低温热水提供所需热量,蒸发的水蒸汽在捕水器中凝结。在一定真空度下,分析了溶质质量分数、热水温度、冷水温度等不同因素对再生性能的影响。以水分蒸发率作为评价指标。实验台操作压力为5kPa,溶质质量分数取值为28%~34%,热水温度区间为56~62℃,冷水温度区间为14~20℃。实验结果表明:溶质质量分数和热水温度对蒸发率的影响较为显著,热水由56℃增加到62℃,蒸发率提高了34.5%。利用混合模型和自定义函数对再生过程进行了数值模拟,模拟结果与实验结果基本吻合。     

水箱水温对CO2热泵热水器性能影响的实验研究

通过实验对比研究了循环加热和一次加热热水时,水箱水温对CO2热泵热水器性能的影响。循环加热工况时,随着水温的升高,压缩机的进、排气压力逐渐升高,功耗增加;气体冷却器的CO2进、出口温度升高,内侧CO2和外侧水的温差逐渐减小,换热量减小;CO2热泵系统的COP下降。一次加热工况时,进水温度一定,系统的各项运行参数稳定,COP基本保持不变。以水温度17℃为例,系统COP在3.5左右,远远高于循环加热的COP。实验结果表明水箱水温对系统的性能有一定影响。根据实验结果提出了水箱结构改进方案,使气冷器入口水温稳定在较低水平,可有效提高系统的性能。     

低位热驱动的工业建筑除湿降温空调系统应用研究

工业建筑低品位余热资源丰富,但较难利用,尤其是80 ℃以下的余热,高效回收利用该温度以下的余热,对于节能环保意义重大。本文提出一种低位热驱动的工业建筑除湿降温空调系统,采用串联方式使热水先后驱动冷水机组和溶液除湿新风机组,从而实现低品位热的梯级深度利用。系统应用热湿解耦处理技术,使溶液除湿新风机组处理空气潜热负荷,冷水机组处理空气显热负荷。工程应用结果表明：在热源温度呈周期波动且均值为77.2 ℃的条件下,冷水机组的平均COP为0.69,冷水机组可提供15.1~16.3 ℃的高温冷冻水,实现对工业建筑热环境的有效调控。溶液除湿新风机组可将新风含湿量从19.4 g/(kg干空气)处理至11.9 g/(kg干空气),机组的平均除湿效率为61.2%。     

工业加热用高温水源热泵现场运行及经济性分析

为将热泵技术应用扩展至工业加热领域,通过调整压缩机设计、优化热泵流程及系统控制方法,设计了高温热泵并现场测试了其在原油加热场合的应用。研究表明:优化设计的高温热泵系统可提供95℃热水,其1 700 kW加热量可满足工业加热需求;运行中热泵系统制热COP介于3.8到4.8;热泵系统运行过程中压缩机排气温度低于100℃,同时电机温度低于85℃。对高温热泵系统及燃油加热炉的经济性分析显示,热泵系统能耗仅为燃油加热量的44.7%。     

水冷式跨临界CO2商用热泵热水器实验研究

介绍了一种以水为冷却介质的带同热器的跨临界CO2商用热泵热水器实验系统.根据实验数据拟合了压缩机的等熵效率和容积效率公式,并依据相应的国家标准对实验系统进行了"一次加热"方式和"循环加热"方式多个工况的循环性能实验研究.实验结果表明,按照"循环加热"制取热水时,在出水温度为55℃和65℃,系统平均制热COPh值分别达2.14到和2.08;按照"一次加热"方式制取热水时,名义工况下出水温度85℃时制热COPh值为2.82,最大负荷工况下出水温度65℃时制热COPh值为3.68.冷却水进水温度越高,系统效率越低,因此热泵热水器系统更适合于"一次加热"供水系统.     

带热回收的氨制冷雪橇雪道制冰系统的性能分析

针对2022年北京冬奥会延庆地区的雪橇雪道氨制冷循环进行性能分析。研究单独制冷、制冷+热泵辅助热回收两种循环方式的运行性能。研究结果表明,在单独制冷模式下,随着冷凝温度的升高,系统的制冷性能下降;在制冷+热泵辅助热回收模式下,利用回收的热量将冷水预热,当冷凝温度为30℃时,系统综合COP可达到5.46;并且以系统冷凝温度30℃蒸发温度-18℃为例,进行经济性分析,表明回收冷凝热制取生活用水所需的费用仅为热泵直接加热热水的40%。     

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