略论近期溴化锂吸收式制冷机的发展

全球溴化锂吸收式制冷机的市场主要在远东,潜在市场在中东和西亚,欧美的使用有限.我国近期溴化锂吸收式制冷机的生产有较大幅度的提升,近年来蒸汽型机组与大于200kW的直燃型机组生产台数基本上趋于稳定,小容量直燃型机组增长较快.近期溴化锂吸收式制冷机的发展主要是高效化、推广应用于热电冷联产系统、以及回收余热和利用太阳能.走节能型、环保型溴化锂吸收式制冷机之路是发展的必然趋势.     

直燃型溴化锂吸收式冷(温)水机组测试不确定度研究

简要介绍直燃型溴化锂吸收式冷(温)水机组的测试方法,选取名义制冷量为2 100 kW的直燃型溴化锂吸收式冷(温)水机组为研究对象,依据GB/T18362—2008附录A中的试验方法进行测试,同时建立数学模型,对测试结果进行不确定度计算,并分析直接测量参数对不确定度的影响趋势,为更准确地测试直燃型溴化锂吸收式冷(温)水机组性能提供指导。     

浅谈直燃型溴化锂吸收式冷热水机组燃油、燃气系统和排气系统的设计与施工

溴化锂吸收式冷热水机组(溴冷机)按其所用热源分为热水型、蒸汽型、直燃型三种,直燃溴化锂吸收式中央空调机简称直燃机,它是以燃料的直接燃烧作为热源,它是三种分类类型的溴冷机中的一种。本文针对直燃溴化锂吸收式中央空调机的设计施工要点,阐述了作者的一些观点。     

直燃型溴化锂吸收式冷热水机组在上海地区应用与推广

一、前言 直燃型溴化锂吸收式冷热水机组(简称直燃型机组)是以燃油、燃气为热源,水为制冷剂,溴化锂水溶液为吸收剂,在真空状态下,交替制取空气调节和工艺用冷热水的设备。 直燃型机组以热源种类分:可分为燃油型和燃气型。燃油种类有轻柴油和重油。燃     

两效溴化锂吸收式制冷机的几种流程及其比较

两效溴化锂吸收式制冷机装有高、低压两发生器和高、低温两个换热器。高压发生器产生的冷剂蒸汽再次用作低压发生器的热源,这样,不仅有效地利用了冷剂蒸汽的潜热,而且减少了机器的排热量。因而制取单位冷量所需的加热量与冷凝器的热负荷均可减少,机组的热效率大为提高。双效溴化锂制冷机(尤其以蒸汽为动力的双效机组),     

上海南新雅饮食城及新雅粤菜馆空调设计

本文简要介绍了南新雅饮食城及新雅粤菜馆暖通设计的冷热源配置,直燃型溴化锂吸收式冷温水机组机房及其烟道设计中的体会.     

多效溴化锂吸收式制冷机

多效溴化锂吸收式制冷机是以蒸汽、热水和燃油燃气等为热源,水为制冷剂,溴化锂为吸收剂的制冷设备.由于其无污染、节电等优点得到广泛应用.直燃型溴化锂吸收式冷水机组由于直接使用一次能源(燃油、燃气),既可制冷又可供热,提高了能源利用率,缓解了夏季用电紧张状况,对城市繁华地区无蒸汽供应的用户特别欢迎.可节省电力增容费和支配电设备的费用,有独特的优势.日本能源比较紧缺、电力供应紧张.溴化锂吸收式制冷机早已得到广泛的普及,目前在中央空调系统中占90%以上,1993年生产50冷吨以上的机组达3500多台.90年代以来,由于CFC禁用期限的迫近,作为替代氟里昂类制冷机的理想机组,溴化锂制冷机在欧洲、美国、东南亚等地越来越多受到重视和采用.     

燃气空调及其应用系列讲座（2）——第2章 燃气溴化锂吸收式冷（热）水机（第1部分）

本文简要说明了溴化锂吸收式冷(热)水机组的分类;燃气溴化锂吸收式冷(热)水机组的选用,对几种可供选用的机型作了简要介绍;此外还介绍了高效率、紧凑型溴化锂吸收式冷(热)水机组与制取0℃以下冷源的溴化锂吸收式冷水机组等燃气溴化锂吸收式冷(热)水机组新技术.     

燃气空调及其应用系列讲座（3）：第2章 燃气溴化锂吸收式冷（热）水机（第2部分）

本文简要说明了溴化锂吸收式冷(热)水机组的分类;燃气溴化锂吸收式冷(热)水机组的选用,对几种可供选用的机型作了简要介绍;此外还介绍了高效率、紧凑型溴化锂吸收式冷(热)水机组与制取0℃以下冷源的溴化锂吸收式冷水机组等燃气溴化锂吸收式冷(热)水机组新技术.     

蒸汽型溴化锂吸收式冷温水机组的设计与优化

根据溴化锂吸收式制冷机冷却负荷大的特点，本文提出了一种蒸汽型溴化锂吸收式冷温水机组的设计和优化方法，给出了所设计的６００ＫＷ制冷量冷温水机组的工作参数和技术指标，并通过与蒸汽单效溴化锂吸收式制冷机的性能比较和对本机组的节能效益和有效能利用率分析，认为蒸汽型溴化冷温水机组是一种值得大力推广的机型。     

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.     

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.     

Numerical study of methods of linearization of the output characteristics of radio-frequency sensors of the level of dielectric media

Different constructions of the sensing elements of radio-frequency level sensors based on sections of long lines are numerically investigated by means of the Matlab program for the purpose of minimizing the measurement error caused by the nonlinearity of the output characteristic. It is shown that the nonlinearity is lowest for U-shaped designs. The nonlinearity factor KN may be regulated by varying the capacitance of a correcting capacitor connected to the input of the sensing element and (or) the length of one of the sections of the long line. In selecting an optimal capacitance of the correcting capacitor KN ≤ 0.15% for control media with dielectric permittivity in the range 2.2–30.     

Possibilities of Decreasing the Errors of Determination of the Height of the Pole of a Sessile Drop of Melt

We analyze the possibilities of decreasing the errors of measuring the height of the pole of a sessile drop of melt above its equator by determining the position of the equator according to the midpoints of vertical chords of the image of the drop. The optimal distance between these chords and the edge of the image of the drop is chosen within 10–20% of the radius of the equator. The proposed method guarantees the same level of errors of evaluation of the height of the pole and the radius of the equator, which enables one to substantially increase the accuracy of evaluation of the capillary constant and the surface energy of the melt according to the geometric parameters of the sessile drop.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.