第三代发泡剂HFC-245fa

介绍了 1 ,1 ,1 ,3,3 五氟丙烷 (HFC 2 4 5fa)的各种性质。HFC 2 4 5fa作为CFC 1 1和HCFC 1 4 1b的长期替代品 ,已成为第三代发泡剂     

CFC动态

AlliedSignal开发HCFC－141b替代品据报道，AlliedSignal公司选定HFC－245fa作为HCFG141b发泡剂的替代品。AlliedSignal公司认为，HFG245fa的ODP值为0，GWP值很低，且具有相当好的发泡特性，为替代HCFC－141b的第三代发泡剂的最佳选择，其发泡材料主要用于大楼、建筑、运输系统及家电用品。该替代品目前仍属产品开发阶段，有很多的毒性测试仍在进行，还需要进行市场评估。AlliedSignal公司目前制造HCFG141b。HCFC－22、HCFC－142b及HFC－134a等硬质发泡剂。溴化甲烷新替代品由于溴化甲烷会破坏臭氧层，因此蒙特利尔议定…     

国际CFC和BFC学术会议在沪举行

由中国化学会委托中科院上海有机化学研究所主力的“国际CFC和BFC(哈龙)学术会议”于1994年8月8～10日在上海举行。 会议主题是研讨CFC和BFC及其替代物的理论研究和生产应用的最新进展。 美国杜邦公司代表在会上介绍了生产CFC替代品的催化反应和催化剂特性的最新进展;美国联信公司介绍了HCFC—141b用于发泡剂的特点和性质;英国ICI公司介绍了英国CFC和HCFC替代物研究的进展,及该公司以KLEA60、KLEA61、KLEA66分别替代     

日本电冰箱告别CFC

今年底,日本将用HCFC和HFC全部替代冰箱生产中使用的CFC(即制冷剂R12和发泡剂R11)。预计到2020年,全部停止使用HCFC。 松下、日立、三菱电机、夏普新推出的电冰箱均用R134_a制冷剂,发泡剂有的用R141b,有的采用环戊烷,为补偿R134_a,替代R12后性能降低5～10％,日立公司开发新     

美国环境保护署将出版CFC_s替代品安全性手册

美国环境保护署将出版部分CFC_s替代品安全性手册。该手册将收录已经获得批准可用于冷出机组、房间空调器等制冷设备的替代CFC_s制冷剂。这些替代制冷剂包括HFC—134a、HCFC—123、HCFC—141b、HCFC—124、HFC—125、HFC—32、HFC—152a等等。有关人士指出,由于HCFC—141b对臭氧层损害能     

冰箱替代工质HFC152a和HFC152a/HCFC22的压缩机性能试验研究

对冰箱制冷剂CFC12及其可能替代物HFC152a和不同配比的HFC152a/HCFC22进行了压缩机性能试验。分别测定了它们的制冷量、单位功率制冷量。试验结果表明以HFC152a取代CFC12,单位功率制冷量提高4.2％、制冷量下降4.7％。在HFC152a中加入少量HCFC22以后,综合性能有所提高;加入较多HCFC22时,则随HCFC22成分增加,混合工质的单位功率制冷量下降,而制冷量上升。HFC152a和HFC152a/HCFC22是一种热工性能优良,是CFC12的优秀替代工质。在冰箱中应用前景十分广阔,     

小型制冷装置应用混合工质的研究

本文介绍了应用非共沸混合物的小型制冷系统的特性。将不同配比的HFC152a/HCFC22双组分混合工质用于冰箱中。实验室进行的试验表明,以适当配比构成的HFC152a/HCFC22混合工质可用于替代家用制冷设备中的CFC12。     

高温工质HFC236ea热物性数学模型及其lgp-h图

高温工质热物性及其完整数学描述是推广应用该类工质的基础,HFC236ea是一种被看好的远期替代CFC11和HCFC123的理想候选工质,也是CFC114较合适的替代品。以试验数据为基础,采用Soave—Redlich—Kwong方程,辩识了HFC236ea的状态方程;基于基团原理,建立了HFC236ea的气体定压比热容模型;由Oausius—Clapegron方程得到了HFC236ea的汽化潜热模型;利用多项式模型,拟合了HFC236ea的粘度、导热系数等迁移性质模型;最后,根据计算结果,绘制了lgp—h图。结果表明,上述模型和图表的精度能够满足HFC236ea在设备研发和制造中的应用要求。     

房间空调器用HCFC22替代物的试验研究

本文介绍了房间空调器应用HCFC22/HCFC142b、HCFC22/HFC152a、HFC32/HFC152a非共沸混合工质的模拟计算及试验研究情况,通过理论计算和大量的测试表明,上述混合工质是HCFC22很有希望的替代制冷剂,它不仅提高了空调器的能效比,有很高的节能意义,而且减少(或没有)了对大气O_3层的危害,为开发HCFC22的替代工质和研制无公害的节能型家用空调器提供了理论及实践基础。     

关于CO_2作为环保制冷剂的性能分析

针对CFC和HCFC及HFC类制冷剂对大气臭氧层、全球温室效应影响问题,采用对比分析方法,分析了CO_2作为替代制冷剂的明显优势和不足及应用前景。结果表明,CO_2是理想的环保制冷剂之一,随着制冷与空调技术领域的发展必将会得到广泛应用。     

Nucleate boiling heat transfer coefficients of pure halogenated refrigerants

Nuclate pool boiling heat transfer coefficients (HTCs) of HCFC123, CFC11, HCFC142b, HFC134a, CFC12, HCFC22, HFC125 and HFC32 on a horizontal smooth tube of 19.0 mm outside diameter have been measured. The experimental apparatus was specially designed to accomodate high vapor pressure refrigerants such as HFC32 and HFC125 with a sight glass. A cartridge heater was used to generate uniform heat flux on the tube. Data were taken in the order of decreasing heat flux from 80 to 10 kW m⁻² with an interval of 10 kW m⁻² in the pool of 7 °C. Test results showed that HTCs of HFC125 and HFC32 were 50–70% higher than those of HCFC22 while HTCs of HCFC123 and HFC134a were similar to those of CFC11 and CFC12 respectively. It was also found that nucleate boiling heat transfer correlations available in the literature were not good for certain alternative refrigerants such as HFC32 and HCFC142b. Hence, a new correlation was developed by a regression analysis taking into account the variation of the exponent to the heat flux term as a function of reduced pressure and some other properties. The new correlation showed a good agreement with all measured data including those of new refrigerants of significantly varying vapor pressures with a mean deviation of less than 7%.     

Evaluation of supplementary/retrofit refrigerants for automobile air-conditioners charged with CFC12Evaluation des frigorigènes supplémentaires / de remplacement pour des systèmes de conditionnement d'air automobiles utilisant du CFC12

In this study, thermodynamic performance of supplementary/retrofit refrigerant mixtures for CFC12 used in existing automobile air-conditioners was examined. A thermodynamic computer analysis of an automobile air-conditioner was carried out for the initial screening of possible mixture candidates, and refrigerant mixtures composed of HCFC22, HFC134a, HCFC142b, RE170 (dimethylether), HC290 (propane), and HC600a (iso-butane) were proposed to supplement CFC12. Also a breadboard type refrigeration test facility was manufactured to verify the performance of the alternative refrigerant mixtures proposed through the computer analysis. Test results showed that HFC134a/RE170 mixture with zero ozone depletion potential is the best long term candidate to supplement CFC12. On the other hand, HCFC22/HFC134a/RE170 and HCFC22/HFC134a/HCFC142b mixtures are good only as short term supplementary/retrofit alternatives since they contain HCFC22. A hydrocarbon mixture of HC290/HC600a showed a good performance but its use in existing automobile air-conditioners should be carefully considered due to its flammability.     

三氟碘甲烷作为冰箱制冷剂的理论循环分析

通过对环保工质三氟碘甲烷(CF3I)的饱和蒸汽压曲线、冰箱名义工况和变工况下循环性能等三方面的理论分析,发现CF3I和CF3I的摩尔组成在50%-65%范围的CF3I/HC290混合工质,理论循环性能与CFC12接近,具有作为冰箱中CFC12灌注式替代物的潜力.     

Comparative assessment of HFC134a and some refrigerants as alternatives to CFC12

A composite plot relating evaporating temperature T_EV, condensing temperature T_CO, pressure ratio (PR) and theoretical Rankine coefficient of performance (COP)_RR is presented for HFC134a. The theoretical performance of HFC134a has been comparatively assessed along with HCFC22, HFC134, HFC152a, HCFC124 and HCFC142b as alternatives to CFC12 by using the standard refrigeration parameters including pressure ratio, specific compressor displacement, theoretical Rankine coefficient of performance, shaft power per ton of refrigeration. A discussion of the practical implications of the choice of the alternatives to CFC12 is also presented.     

A study on the performance of multi-stage heat pumps using mixturesEtude sur la performance de pompes à chaleur multi-étagées utilisant des mélanges

Multi-stage heat pumps composed of a condenser, evaporator, compressor, suction line heat exchanger, and low and/or high stage economizers are studied by computer simulation. Their thermodynamic performance and design options are examined for various working fluids. In the simulation, HCFC22/HCFC142b and HFC134a are studied as an interim and long term alternatives for CFC12 while HFC32/HFC134a and HFC125/HFC134a are studied as long term alternatives for HCFC22. The results indicate that the three-stage super heat pump with appropriate mixtures is up to 27.3% more energy efficient than the conventional single-stage system with pure fluids. While many factors contribute to the performance increase of a super heat pump, the most important factor is found to be the temperature matching between the secondary heat transfer fluid and refrigerant mixture, which is followed by the use of a low stage economizer and suction line heat exchanger. The contribution resulting from the use of a high stage economizer, however, is not significant. With the suction line heat exchanger, the system efficiency increases more with the fluids of larger molar liquid specific heats. From the view point of volumetric capacity and energy efficiency, a 40%HCFC22/60%HCFC142b mixture is proposed as an interim alternative for CFC12 while a 25%HFC32/75%HFC134a mixture is proposed as a long term alternative for HCFC22.     

氟里昂CFC、HCFC的替代情况介绍

由于氟里昂CFC类和HCFC类会破坏地球臭氧层及产生温室效应,到2040年将全面禁用,这里介绍几种替代制冷剂的情况。     

HCFC——一类过渡发泡剂

简单地介绍了几种用于聚氨酯泡沫塑料的ＣＦＣ替代物——ＨＣＦＣ发泡剂的性能特点。     

Performance evaluation of environmentally benign refrigerants in heat pumps 1: A simulation study

An overview of the performance characteristics of possible working fluids in vapour-compression industrial heat-pump systems for medium to high temperature applications is presented. The refrigerants studied include HFC12, HCFC22 HFC134a, HCFC142b, HFC152a, a tenary blend of HCFC22 (40%), HCFC124 (43%) and HFC152a (17%), and NH₃. The calculations are made for all the refrigerants for the same operating conditions and are compared with each other. For high-temperature applications, a compression- absorption heat-pump cycle (with NH₃-H₂O as the working fluid) is described. Its performance characteristics are discussed and compared with vapour-compression cycles with HCFC142b as the working fluid by using the concept of ‘thermodynamic temperature’.     

Condensation heat transfer coefficients of enhanced tubes with alternative refrigerants for CFC11 and CFC12Coefficients de transfert de chaleur de condensation de tubes à surface augmentée fonctionnant avec des frigorigènes de remplacement de CFC11 et de CFC12

In this study, condensation heat transfer coefficients (HTCs) of a plain tube, low fin tube, and Turbo-C tube were measured for the low pressure refrigerants CFC11 and HCFC123 and for the medium pressure refrigerants CFC12 and HFC134a. All data were taken at the vapor temperature of 39°C with a wall subcooling of 3–8°C. Test results showed that the HTCs of HFC123, an alternative for CFC11, were 8.2–19.2% lower than those of CFC11 for all the tubes tested. On the other hand, the HTCs of HFC134a, an alternative for CFC12, were 0.0–31.8% higher than those of CFC12 for all the tubes tested. For all refrigerants tested, the Turbo-C tube showed the highest HTCs among the tubes tested showing almost an 8 times increase in HTCs as compared to the plain tube. Nusselt's prediction equation yielded a 12% deviation for the plain tube data while Beatty and Katz's prediction equation yielded a 20.0% deviation for the low fin tube data.