浅析电冰箱制冷循环与节能

对比了电冰箱单路、双路、多路循环及双机、双级制冷循环,分析了其能耗状况,进行了成本、系统匹配性、市场占有率及其cop值比较.针对双路循环存在的濒繁开停机现象,提出了完善控制方式及采用双稳态电磁阀的变温技术.变温室蒸发器与冷冻室蒸发器串联,其前串联双稳态电磁阀2,并在变温室蒸发器上并联双稳态电磁阀1,据变温室温度设定改变双稳态电磁阀通断实现两个循环支路交替制冷.冷藏室温度控制压缩机启停,变温室温度仅控制双稳态电磁阀通断,实现切换制冷剂流向目的.应用该循环方式及相关措施研制的BCD-186CHS直冷电冰箱最大负荷日耗电0.39度,在变温情况下耗电在0.35度以下,最低达0.31度.     

直冷电冰箱制冷系统优化设计探析

冷冻室蒸发器采用多层换热片的复合立体结构,在S型制冷盘管壁外侧固定套装翅片,增加冷冻室顶部和低部两个高温区制冷量.将冷冻室按1:1划分出变温室,通过其中温度传感器控制双稳态电磁阀通断实现制冷剂回路切换,将变温室按冷冻、软冷冻、冷藏使用,也可关闭.通过横、竖盘管混排结构的丝管式冷凝器设计,借助制冷系统压缩机、冷凝器、蒸发器负荷匹配及其与毛细管制冷剂流量匹配,通过防凝露管走向及位置设计、蒸发器管道位置及走向布置和回气换热器设计,研制的BCD-186CHS直冷电冰箱最大负荷日耗电0.39度,在变温室为节能状态时耗电在0.35度以下,最低达0.31度.     

直冷冰箱变温控制技术

本文提出了一种实现直冷冰箱变温控制的方法 ,并依据该方法制作了直冷变温冰箱。该冰箱的变温室温度可以在 5℃到 - 18℃之间调节 ,使变温室可以作为冷藏室、冰温室、微冻室和冷冻室使用。变温室作为冷藏室、冷冻室等不同功能间室使用时 ,对直冷变温冰箱的储藏温度和耗电量也进行了测试 ,测试结果表明该方法是可行的     

不同循环冰箱的性能比较

本文讨论了两种双蒸发器冰箱的节能效果,一种是将两个蒸发器串联,另一种是将两个蒸发器各自构成独立的循环,两个独立循环可用电磁阀切换,或两循环采用各自的压缩机、冷凝器而构成彼此完全独立的循环.分析和试验表明,在研究的工况下,与单蒸发器冰箱相比,串联蒸发循环可节能20%,而电磁阀控制的交替蒸发循环比串联循环节能12.3%;彼此完全独立的双循环冰箱,与美国现行标准相比节能13.8%.     

冰箱冷藏室蒸发器离层的危害及解决方法

蒸发器离层问题一直是电冰箱产品的一大质量难题，冰箱冷藏室蒸发器离层，不仅影响冰箱的制冷效果，缩短压缩机的使用寿命，同时增加耗电量，提高了用户的使用成本。本文针对直冷冰箱冷藏室蒸发器的离层原因，造成的损失，解决的方法及效果进行了详细的分析。     

气液两相流流型振荡诱发制冷循环不稳定性的实验研究

研究利用变制冷剂流量制冷循环的实验平台结合流动显示方法发现:1)蒸发器出口的制冷剂气液两相流流型存在过热蒸汽流和雾状流两种型式,二者之间存在一个转变过渡区域,此时,两种流型闪动交替出现,回气温度随机性波动;2)膨胀阀出口(即蒸发器入口)的制冷剂气液两相流的流型存在液一气分相流、泡一气分相流两种型式,二者之间也存在一个转变过渡区,此时两种流型交替出现,制冷循环周期性振荡,蒸发温度、回气温度、排气温度等参数周期性波动:且振荡周期随着制冷循环制冷剂流量的增大而缩短.     

BCD—225微电脑控制双温双控电冰箱的性能测试分析（二）串并流程

为了提高电冰箱产品的挡次和技术水准, 合作进行将ＢＣＤ２２５ 型电冰箱改装成微电脑控制、双稳态电磁阀进行制冷量分配调节、二间室温度独立可调的智能化冰箱。试装完成后,所有系统方面的性能测试均符合现行标准的要求,在实现电冰箱节能、多功能、智能化的道路上前进了一大步, 同时它还缩短了新产品的研制周期。     

多主机制冷机房变流量解耦控制策略研究

在单主机制冷机房变流量解耦控制策略基础上,探讨了多主机制冷机房的变流量解耦控制策略。在考虑冷水机组COP值同时是冷负荷及冷却水进水温度的函数基础上,通过比较不同冷负荷分配策略对制冷机房能耗的影响,得到了在大多数负荷区间,采用均匀分配总冷负荷的策略最为节能。这说明,前期关于单主机制冷机房变流量变温差控制方式可推广至多主机制冷机房变流量控制。     

热管复合式制冷机组的研发与应用

研发了一种适用于数据中心等电子设备全天候环境控制的新型高效制冷机组HKF-60FH,其集成蒸气压缩制冷系统、分离式热管系统于一体,具有压缩制冷、复合制冷和热管制冷三种工作模式。压缩制冷单元由4台涡旋式压缩机两两并联构成2个独立的制冷回路,通过变容量控制实现制冷量调节;热管单元使用第二制冷剂,由液泵驱动强制循环;风冷侧采用组合式换热器,其由热管单元的换热器、压缩制冷单元的冷凝器和风机构成。高温季节运行压缩制冷模式,压缩制冷系统的第一制冷剂通过冷凝蒸发器为第二制冷剂提供全部冷量;过渡季节运行复合制冷模式,热管单元满负荷工作,不足冷量由压缩制冷单元提供;低温季节运行热管模式,全部使用自然冷源。HKF-60FH配套应用于某高性能计算机的空调系统,蒸发器设置在服务器桁架内,采用水平送风、闭式循环的气流组织方式,回风温度设定为33℃。性能测试显示:制冷工况(环境温度35℃)和热管工况(环境温度10℃)的制冷量/COP分别为61.3 k W/3.23和59.8 k W/11.3。     

基于冰浆蓄冷的集中制冷冷藏陈列柜的实验研究

冷藏陈列柜是超市、卖场等场所经常使用的制冷保鲜设备,这里将冰蓄冷技术应用于冷藏陈列柜,以冷水作为循环介质,开发一种基于动态冰浆蓄冷的集中制冷冷藏陈列柜新型产品.集中制冷模式将制冷机组和陈列柜柜体分离,没有冷凝器放热;动态冰蓄冷可以充分利用低谷电力;采用冷水作为循环介质,蒸发器的温度处于0℃以上,杜绝了结霜和融霜问题,因此大幅度降低了冷藏陈列柜的能耗.新型冷藏陈列柜的柜内温度场分布实验结果表明:冰浆集中制冷冷藏陈列柜在一定的运行条件下完全可以达到现有冷藏陈列柜的保温效果,而且温度波动很小.     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Assessment of intakes of mixtures of radionuclides

Australia has several uranium mines and a large number of mineral sand mines, with associated processing facilities. Exposures resulting from these mining and processing operations usually involve intakes of mixtures of radionuclides. This work describes the development of a suite of first order, linear compartment models, based on the ICRP Publication 66 respiratory tract model, and an analytical solution to the decay equations, for assessing the consequences of such intakes. The computer programs based on these models directly compute excretion, organ retention and organ and whole-body doses for intakes of either single radionuclides or any mixture of radionuclides belonging to the same radioactive decay chain. The intake can be via inhalation, ingestion or injection, and can be acute, chronic or of limited duration. The starting concentration and degree of secular (dis)equilibrium can be specified for each radionuclide. No assumptions need to be made about the relative magnitudes of the radioactive half-lives of the different nuclides.     

卧式金属罐容量的测量结果不确定度

本文根据多年的实践检定经验 ,参照JJF1 0 59- 1 999《测量不确定度评定与表示》以及《测量不确定度表达 1 0讲》 ,对卧式金属罐容量的测量结果不确定度进行了评定。     

盐酸浓度不确定度的评估

通过对盐酸浓度标定的过程分析，找出影响结果的各个分量，进行不确定度的评定，按照计量技术规范给出标准的表示法。     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of anisotropy of properties on the basis of studies of texture of coarse-grained ingots of thermoelectric materials

An analysis of anisotropy of the properties of a Bi₂Se_0.3Te_2.7 solid solution was carried out using construction of demonstrative surfaces for thermoelectric effectiveness and thermal expansion coefficients. It is shown that the texture is an important factor forming anisotropy of properties and technological fitness of ingots for manufacturing modules. Anisotropy of properties based on the studies of the ingot textures obtained using the float-zone method and Bridgman method (growing thermoelectric plates in a flat cavity) was studied.