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1.
随着CFC和HCFC类物质淘汰进度的加快,液氨毒性和安全性的限制,CO2作为制冷剂的使用也越来越被人们看好。CO2／NH3复叠式制冷技术的提出和应用在国内虽然做了不少的研究和试验,但是大多集中在系统循环的分析和系统的优化。本文从CO2／NH3复叠式在冷冻冷藏工程中的应用方面对有关技术问题进行了分析。 相似文献
2.
In this study, an experimental setup is designed and built to investigate the feasibility and performance of the proposed
dual-mode cascade refrigeration cycle. The apparatus can be operated in two modes: dual-stage mode and single-stage mode such
that the low temperature cycle (LTC) can be operated together with the high temperature cycle (HTC) or can run independently.
Experimental results validate the feasibility of independent operation of LTC. The performance of the independent operation
of LTC mode is theoretically investigated using experimental data as bases. Detailed suggestions are made for the improvement
of the coefficient of performance (COP) of the experimental system. Theoretically, high COP of the cycle provides excellent
application for the presented refrigeration cycle. 相似文献
3.
二氧化碳低温制冷循环分析 总被引：1，自引：1，他引：0
钱怀洲 《顺德职业技术学院学报》2010,8(2):7-9
对两种不同的二氧化碳双级压缩低温制冷循环进行了分析．得到在一定的蒸发温度和冷却器出口温度下．一次节流不完全中间冷却二氧化碳双级压缩循环COP较大、最优冷却压力较低、具有良好的发展前景。 相似文献
4.
提出了采用太阳能、天然气联合驱动的扩散吸收式冰箱空调复合机总体设计方案,对其中相关技术问题进行了论述,重点对扩散吸收式制冷机工质的选择进行了探讨。通过对扩散吸收式系统常用的NH3／H2O,NH3／NaSCN,NH3／LiNO3吸收制冷工质对进行分析比较,认为在综合考虑系统的性能系数、最低制冷温度、溶液结晶、溶液比热和粘度等因素后,以选用LiNO3／NH3／He作为复合机中扩散吸收式制冷机的工质为好。 相似文献
5.
针对氨水吸收/压缩复合制冷循环的方式不同,结合Schulz氨水溶液状态方程,分别对压缩机处于系统高压区和低压区2种不同的组合方式进行了理论分析计算.分析了在给定中间压力下,蒸发温度Te、热源温度Th和冷却水温度Tw对2种组合方式下压缩机当量热耗量qCW、热源耗热量qG和循环性能系数COP的影响.结果表明:压缩机当量热耗量对循环性能系数的影响要低于热源耗热量的影响;压缩机处于系统高压区时循环的一次用能量要明显高于压缩机处于系统的低压区;压缩机处于系统低压区时循环性能要优于压缩机处于系统的高压区.当中间压力给定时,存在一个最佳热源温度,使得氨水吸收/压缩复合制冷循环的性能系数取得最大值. 相似文献
6.
7.
王寒栋 《深圳职业技术学院学报》2012,11(5):3-10
在一种太阳能驱动、采用喷雾吸收器并以板式换热器作为主要换热部件的LiNO3-NH3-He三工质扩散吸收式制冷系统中,根据试验测得的运行参数,以溶液的p-t-x西方程及物性方程、传热基础理论等为依据,提出了计算溶液换热器中溶液流量的方法,并利用综合传热系数k、传热单元数N_TU与换热器效率s研究了板式换热器作为LiN03-NH3-He扩散吸收式制冷系统发生器、冷凝器、溶液热交换器、溶液冷却器时的换热性能．试验与分析表明,板式换热器的换热面积及其内部流道中的流量（流速）对其综合传热性能具有较大影响;在介质流量一定时,板式换热器不宜考虑过大的面积预留量;板式溶液换热器内部流道宜采用多流程布置形式以强化传热、提高换热效率． 相似文献
8.
Attheendoftheyear2000,annualglobalfluo rocarbonrefrigerantemissionfrommobileandunitaryairconditioningequipmentsislikelytosurpass100000tons,correspondingtoaglobalwarmingim pactofmorethan150milliontonsofCO2.Evenlar gerindirectCO2emissionresultsfromthegeneration ofpowerconsumedtodrivethesystems[1].Within creasingfocusongreenhousegasemissionreductions,strictregulationsontheuseofsynthesizedrefrigerants suchasHCFCsandHFCsmaybeexpected,possiblyfollowedbyphase outtargetsanddates.Theinterna tionale… 相似文献
9.
Theoretical and experimental analysis of a new refrigerant mixture BY-3 was conducted based on a single-stage vapor compression refrigeration system. The water-water heat pump system used BY-3 to produce hot water when the low temperature was 20 ℃. The following results were obtained: the highest temperature at the condenser outlet reached about 85 ℃; when the difference between the water temperatures at the condenser outlet and the evaporator inlet was less than 40 ℃, the coefficient of performance (COP) was larger than 4; when the difference reached 55 ℃, the COP still kept 3; the discharge temperature of BY-3 was lower than 100 ℃, and the refrigerant vapor pressure kept lower than 1.8 MPa. When the water temperature at the condenser outlet reached over 85 ℃, nearly a 5 ℃ superheating temperature was maintained. 相似文献
10.
Mechanicalvapourcompressioncyclesaremainlyemployedinmostrefrigerationsystems .Chlorofluoro carbons(CFCs)orhydrochlorofluorocarbons(HCFCs)aregenerallyusedasrefrigerantsinthesesystemsdrivenbyelectricityfromburningfossilfuels ,whichresultsino zonedepletionduetotheleakageandpoorrecoveryofthoseman maderefrigerants,andglobalwarmingowingtoCO2 emissionfrom powerstationsandthereasonisthatCFCsorHCFCsarepowerfulgreenhousegases.Inaddition,otherenvironmentalissuesarealsocausedbytheNOx,SO2 andpartic… 相似文献
11.
System design and analysis of the trans-critical carbon-dioxide automotive air-conditioning system 总被引：1，自引：0，他引：1
INTRODUCTIONAftertheKyotoProtocolwassigned ,theworldwiderefrigerationandair conditioningin dustryfaceduptogreatchangesintheenviron mentalproblem .Forautomotiveair conditioning(AAC) ,thecurrentrefrigerant,R 13 4a ,hasbeenregardedasrestricted use refrigeran… 相似文献
12.
Experiment and mechanism investigation on advanced reburning for NOx reduction： influence of CO and temperature 总被引：4，自引：0，他引：4
Wang ZH Zhou JH Zhang YW Lu ZM Fan JR Cen KF 《Journal of Zhejiang University. Science. B》2005,6(3):187-194
Pulverized coal reburning, ammonia injection and advanced reburning in a pilot scale drop tube furnace were investigated. Premix of petroleum gas, air and NH3 were burned in a porous gas burner to generate the needed flue gas. Four kinds of pulverized coal were fed as reburning fuel at constant rate of 1g/min. The coal reburning process parameters including 15%～25% reburn heat input, temperature range from 1100 ℃ to 1400 ℃ and also the carbon in fly ash, coal fineness, reburn zone stoichiometric ratio, etc. were investigated. On the condition of 25% reburn heat input, maximum of 47% NO reduction with Yanzhou coal was obtained by pure coal reburning. Optimal temperature for reburning is about 1300 ℃ and fuel-rich stoichiometric ratio is essential; coal fineness can slightly enhance the reburning ability. The temperature window for ammonia injection is about 700 ℃～1100 ℃. CO can improve the NH3 ability at lower temperature. During advanced reburning, 72.9% NO reduction was measured. To achieve more than 70% NO reduction, Selective Non-catalytic NOx Reduction (SNCR) should need NH3/NO stoichiometric ratio larger than 5, while advanced reburning only uses common dose of ammonia as in conventional SNCR technology. Mechanism study shows the oxidization of CO can improve the decomposition of H2O, which will rich the radical pools igniting the whole reactions at lower temperatures. 相似文献
13.
In this paper, a new ternary non-azeotropic mixture of HFC-161/125/143a (0.15/0.45/0.40 in mass fraction), as a promising
mixed refrigerant to R404A, is presented. The ozone depletion potential (ODP) of the new refrigerant is zero and its basic
thermodynamic properties are similar to those of R404A, but its global warming potential (GWP) is much smaller than those
of R507A and R404A. Meanwhile, theoretical calculations show that, under the working condition I (the average evaporation
temperature: −23 °C, the average condensing temperature: 43 °C, the superheat temperature: 28 °C, the subcooling temperature:
5 °C), the volumetric refrigerating effect and specific refrigerating effect of the new mixture are 2.33% and 15.48% higher,
respectively, than those of R404A. The coefficient of performance (COP) of the new mixture is 5.19% higher than that of R404A
and the pressure ratio of the new mixture is 0.82% lower than that of R404A. Equally, under the working condition II (the
average evaporation temperature: −40 °C, the average condensing temperature: 35 °C, the superheating temperature: 30 °C, the
subcooling temperature: 5 °C), the volumetric refrigerating effect and specific refrigerating effect of the new mixture are
2.24% and 20.58% higher, respectively, than those of R404A. The COP of the new mixture is 4.60% higher than that of R404A
and the pressure ratio of the new mixture is similar to that of R404A. The performances of the new mixture and R404A are compared
in a vapor compressor refrigeration apparatus originally designed for R404A under several working conditions (condensing temperatures:
35–45 °C, evaporation temperatures: −40–−20 °C). Experimental results show that the new mixture can obtain a higher COP, by
6.3% to 12.1%, and a lower pressure ratio, by 1.8% to 6.6%, compared to R404A; although the discharge temperature of the new
mixture is slightly higher than that of R404A. The advantages of the new mixture will be further verified in the actual system. 相似文献
14.
用制冷剂Ｒ２２替代制冷剂Ｒ１２减少对大气臭氧层的破坏。文章在理论和实验中对两种制冷剂在制冷量,压缩功,制冷系数等方面加以分析,并在如何改进其制冷性能,提高效益方面作了探讨。 相似文献
15.
余华明 《顺德职业技术学院学报》2008,6(2):15-17
针对使用R134a／R23混合制冷剂的自然复叠制冷系统．编制了基于NISTREFPROP的仿真程序。利用仿真和实验对系统各种优化措施的效果进行了分析和验证。两者都表明：分凝措施有利于降低系统蒸发温度、提高COP;而回热可以略微降低系统蒸发温度,但使系统COP降低、压缩机排气温度升高。 相似文献
16.
S. S. Verma 《Resonance》2001,6(10):57-67
Refrigeration applications at the domestic, commercial and industrial levels are becoming an integral part of the present
day living. The demand and supply of refrigeration systems is increasing day by day with the changing lifestyle. The existing
compressor-based refrigeration (i.e., mechanical refrigeration) system has reached the maximum level of innovation. For the
last few decades, there has not been any significant increase in the efficiency (i.e., coefficient of performance, COP) of
the system. Moreover, with the increasing awareness of environmental degradation, the production, use and disposal of ChloroFluoro
Carbons (CFCs) and HydroChloroFluoroCarbons (HCFCs) as refrigerants in mechanical refrigeration system has become a subject
of great concern. However, such systems are being developed using more ecofriendly refrigerants viz., air, CO2, NH3, etc. Besides, efforts are being directed to develop other types of refrigeration technologies e.g., magnetic refrigeration,
thermoelectric refrigeration (discussed in Part 1) and thermoacoustic refrigeration (discussed in Part 2), which will be moreecofriendly, cost effective, efficient, simple in design, convenient and reliable. 相似文献
17.
本评介绍了用NH_3—NH_4HCO_3浸提氧化铜矿,直接制备饲料硫酸铜的方法.本方法可以充分利用氧化铜矿资源,具有产品质量高、成本低、环境污染小的优点,能产生很好的经济效益. 相似文献
18.
Performance of a single-stage Linde-Hampson refrigerator operating with binary refrigerants at the temperature level of-60 ℃＊ 总被引：1，自引：1，他引：0
The optimization of the performance of a single-stage Linde-Hampson refrigerator （LHR） operating with six different binary refrigerants （R23/R134a, R23/R227ea, R23/R236ea, R170/R290, R170/R600a and R170/R600） with ozone depletion potentials （ODPs） of zero was conducted using a new approach at the temperature level of-60℃. Among these binary refrig- erants, the 0.55 and the 0.6 mole fractions of R23 for R23/R236ea are the most prospective nonflammable ones for the medium and low suction pressure compressors, respectively. For these two kinds of compressors, the 0.6 and the 0.65 mole fractions of R170 for R 170/R600, respectively, are the most prospective binary refrigerants with low global warming potentials （GWPs）. The results of optimization of pressure levels indicate that the optimum low pressure value for coefficients of performance （COP） is achieved when the minimum temperature differences occur at both the hot and the cold ends of the recuperator at a specified composition and pressure ratio. Two useful new parameters, the entropy production per unit heat recuperated and the ratio of heat recuperating capacity to the power consumption of the compression, were introduced to analyze the exergy loss ratio in the recuperator. The new approach employed in this paper also suggests a promising application even to the optimization of the performance with multi-component refrigerants. 相似文献
19.
The optimization of the performance of a single-stage Linde-Hampson refrigerator (LHR) operating with six different binary refrigerants (R23/RI34a, R23/R227ea, R23/R236ea, R170/R290, RI70/R600a and R170/R600) with ozone depletion potentials (ODPs) of zero was conducted using a new approach at the temperature level of-60 ℃. Among these binary refrig-erants, the 0.55 and the 0.6 mole fractions of R23 for R23/R236ea are the most prospective nonflammable ones for the medium and low suction pressure compressors, respectively. For these two kinds of compressors, the 0.6 and the 0.65 mole fractions of R170 for R170/R600, respectively, are the most prospective binary refrigerants with low global wanning potentials (GWPs). The results of optimization of pressure levels indicate that the optimum low pressure value for coefficients of performance (COP) is achieved when the minimum temperature differences occur at both the hot and the cold ends of the recuperator at a specified composition and pressure ratio. Two useful new parameters, the entropy production per unit heat recuperated and the ratio of heat recuperating capacity to the power consumption of the compression, were introduced to analyze the exergy loss ratio in the recuperator. The new approach employed in this paper also suggests a promising application even to the optimization of the performance with multi-component refrigerants. 相似文献
20.
针对废弃热量利用率低的问题,深入研究喷射制冷循环系统的工作原理和主要的内部结构,对喷射制冷循环系统的工作过程进行建模分析,得出系统中主要工作参数之间的数学关系。然后引入蒸汽压缩制冷原理,设计一个增压喷射制冷循环系统,对系统的性能特点进行详细分析,并给出在不同现实需求下的改进优化策略。测试结果表明设计的增压喷射制冷循环系统可以提高低品味的热量的利用率。 相似文献