二甲醚作为汽车空调制冷剂的性能研究

对二甲醚（DME）在用作汽车空调制冷剂与现有R134a汽车空调制冷剂在基础热力性质、汽车空调标准工况和变工况下制冷循环性能进行了对比分析，并作理论计算。分析表明：二甲醚的制冷性能与R134a基本相似，而性能系数COP却优于R134a。因此，更具环保优势的二甲醚是一种理想的潜在的汽车空调制冷剂。     

速冻装置制冷工质R22的替代

本文对替代速冻装置制冷剂R22的单元工质（如R717、R290、R134a)和混合工质（如R407c,R407d,R407e,R410a,R410b,R404a,R507)进行了热力计算和循环分析，结果表明经过不断完善上述工质均有望成为R22的替代工质。     

《新制冷工质热力性质表和图》

本书着重叙述了新工质HCFC-123和HFC-134a的热物理性质,热力性质计算式,以及饱和状态和过热状态下的热力性质。为了方便工程应用,本书提供了2开版面的工质热力性质压-焓图。考虑到R11,R22和NH3等目前常用工质在今后几年或更长时间内仍将被广泛应用,本书亦提供了这些工质的热力性质表     

船用冷藏装置以R134a替代R12作为制冷剂的研究

本文对制冷装置中以R134a替代R12作为制冷剂的运行及需要解决的问题作了分析，通过计算，得出结论认为，在船用制冷装置中用R134a替代R12是可行的，并给出了替换过程中要采取的措施。     

确定MH方程系数的计算机方法及R123热力性质的计算

根据卤代烃制冷工质的临界参数及一对饱和蒸汽参数的实测值,本文给出了确定 MH—59状态方程十一个待定系数的计算机方法。对 R134a 的 p=f(T,v)实验值与计算值的比较表明,压力的最大相对误差不大于1.87%.由此给出了 R123的 MH 状态方程及热力性质的全部计算公式。与采用 MBWR 状态方程的R123热力性质的计算结果比较表明,热力参数中的最大相对误差不大于4.86%。并编制了均采用 MH 状态方程的十四种制冷工质的热力性质通用计算程序。     

新工质R143a热力性质图表研制

根据MBWR状态方程及4个辅助方程式导出了R143a的其它热力性质计算方程,用Visual Basic语言编写了R134a的热力计算程序和压焓图的绘图程序,计算结果与文献[1]进行了比较,并给出了由计算结果编制的热力性质表与压焓图.     

HFCs混合制冷剂热力性质的研究

为了利用PR方程和Huron-Vidal混合规则对三元混合制冷剂的热力性质进行精确计算，通过对10组二元HFCs混合制冷剂的汽液相平衡实验数据进行热力学关联，得出了相应的NRTL模型参数，由优选得到的过量Gibbs自由能NRTL模型的相互作用系数预测了构成R407C和R404A的三元混合制冷剂R32／R125／R134a以及R125／R143a／R134a的汽液相平衡，结果表明，泡点压力实验值和计算值的算术平均相对偏差小于0．42％，各组分的汽相组成实验值和计算值基本吻合。最后还应用相关热力性质分别对R32／R125和R407C进行了理论制冷循环分析计算并和其他模型的计算结果进行了比较。     

二甲醚作为汽车空调制冷剂的性能研究

本文对二甲醚（DME）用作汽车空调制冷剂的性能与现有汽车空调制冷剂R134a进行了对比。首先比较了二甲醚和R134a的基础热力性质，然后对二甲醚和R134a的汽车空调标准工况和变工况下制冷循环性能进行了详细的理论计算及分析。分析表明：二甲醚的制冷性能与R134a基本相似，而性能系数（COP）却优于R134a。因此，更具环保优势的二甲醚是一种理想的潜在的汽车空调制冷剂。     

风冷螺杆热泵机组制冷剂替换试验研究

对R22、R407c、R134a三种制冷剂的基本物性及热力性能进行了分析比较，并在风冷螺杆热泵机组基础上进行了替换试验研究。结果表明：R407c为最佳替换R22的制冷剂；R134a替换后能效比较高，但制冷（热）量衰减过多，同时R134a的运行压力过低不太适合热泵工况。     

二甲醚(DME)制冷性能的实验研究

在二甲醚热物理性质分析的基础上，对二甲醚的制冷性能进行了实验研究，并与常用制冷剂R134a的制冷性能进行对比，结果表明：在同一实验装置上，在相同冷凝温度、不同蒸发温度下的二甲醚的制冷量比R134a约低10％～15％，制冷系数（COP）比R134a低约3％～9％，DME可以直接充注用于R134a制冷系统，可以作为R134a的直接替代物。通过对不同种类的润滑油的实验测试表明：常用的脂类油和矿物油均可用作二甲醚制冷系统的润滑油，使用脂类油时二甲醚排气温度比使用矿物油时稍高，矿物油更适于应用于二甲醚制冷系统。     

R134a和R417A应用于热泵热水器灌注式替代R22的实验分析

在空气源热泵热水器中,对R22、R417A和R134a进行了理论计算及实验分析.结果表明,R417A的制热量和COP更接近于R22,并且排气温度比R22低25℃左右,排气压力也比R22平均低0.17MPa;尽管R134a也具有较低的排气温度和排气压力,但其制热量远远小于R22,低温工况下,吸气压力过低,而且需更换压缩机润滑油,因此,R417A比R134a更适合在空气源热泵热水器中对R22进行直接灌注式替代.     

蒸发器建模仿真与试验的比较

采用稳态分布参数模型对R134a单元机的蒸发器进行仿真。使用改进的Kattan模型对R134a在光滑管内的流动形式进行划分，从而得出流型图。根据流型图，应用不同表达形式的关联式计算管内局部沸腾换热系数。CCWang的模型用于计算百叶窗形翅片管式蒸发器的表面换热系数及压降。析湿系数通过试验数据建立的数据库确定。在仿真过程中，应用隐式三次多项式拟合模型计算R134a的物性。将仿真结果与试验数据对比发现，仿真值能够较为真实的反映机组的运行状态。通过误差分析得出制冷量的平均相对误差为1．12％，出风干球温度的平均相对误差为1．25％，出风焓的最大相对误差为0．88％，R134a出口温度的平均相对误差为4．0％。     

Refrigerant 134a: The first step into a new age of refrigerants

Many papers have been published on R134a within the last four years, beginning from the point when it became apparent that R134a would be the favourite for replacing the most important fully halogenated refrigerant worldwide, R12. This paper summerizes the requirements for a suitable replacement for R12, the criteria leading to the selection of R134a, the developmental efforts that have been made and the results of this process. In particular, chemical properties, material compatibility and thermodynamic properties of R134a are described. Because of the different chemistry in comparison with CFC refrigerants, special requirements for suitable compressor lubricants and system cleanliness are mentioned. Finally, some explanations of installing closed pruduct cycles for CFCs and their substitutes are given.     

Performances d'une machine tritherme à éjecteur utilisant des mélanges de fluides frigorigènesPerformance analysis of a jet cooling system using refrigerant mixtures

The optimisation of a jet cooling system using refrigerant mixtures as substitutes of pure refrigerants has been investigated. A steady-state simulation program, for given temperatures of the sources, integrating simple models of each component has been developed. A Peng-Robinson equation of state assuming equality of the fugacities of the two phases was used to model the thermodynamic properties of the vapour and liquid-vapour equilibrium. The refrigerants investigated in this study are: the pure refrigerants R142b, R152a, RC318, R124, R134a, R22 and the binary refrigerants R22/RC318, R22/R142b, R22/R124, R22/R152a, R22/R134a, R134a/R142b, R152a/R142b and R134a/R152a. Results show that the use of a binary mixture does not always increase the performance of system. Generally, when the mixture is strongly zeotropic (e.g.: R22/RC318), the cooling efficiency of the system decreases. However, when the mixture is mildly zeotropic (e.g. R134a/R142b) or almost azeotropic (e.g. R134a/R152a), efficiency and energetic efficiency increase.     

神经网络模型在制冷剂物性参数计算中的应用

介绍采用BP，RBF和Elman神经网络计算制冷剂物性参数的方法。以R11，R134a和近共沸混合制冷剂R410A为研究对象，分别建立三种制冷剂的BP，RBF和Elman网络饱和物性参数计算模型。根据该模型由已知温度求各制冷剂在饱和气和饱和液状态下的其他物性参数值，通过与REFPROP软件计算结果进行对比，证明BP，RBF和Elman神经网络物性计算模型具有很高的精度，可以用于物性参数的计算，是一种新的物性计算方法。     

Exergy analysis of R1234yf and R1234ze as R134a replacements in a two evaporator vapour compression refrigeration system

Exergy analysis is a useful way for determining the real thermodynamic losses and optimising environmental and economic performance in the systems such as vapour compression refrigeration systems. The present study deals with the exergy analysis on a two evaporator vapour compression refrigeration system using R1234yf, R1234ze and R134a as refrigerants. In the calculation of losses occurring in different system components, besides the exergy efficiency of the refrigeration cycle, a computer code was developed by using Engineering Equation Solver (EES-V9.172-3D) software package program. The effects of the evaporator and condenser temperatures on the exergy destruction and exergy efficiency of the system were investigated. R1234yf and R1234ze, which are good alternatives to R134a concerning their environmentally friendly properties and this is the most significant finding emerging from this study.     

制冷工质R22热力性质的一种快速算法

制冷工质热物性的计算是数值模拟技术非常重要的一个环节，开展这一工作的研究且有重要的价值。本文在结合Martin-Hou方程的基础上提出了制冷工质热力性质的一种快速算法，经实例验证，该算法具有精度高、适应范围广、稳定性好等特点，可供制冷工质热物性算法设计的初学者作参考。     

A generalized correlation for two-phase flow of alternative refrigerants through short tube orifices

The objective of this study is to develop a generalized correlation for the prediction of refrigerant flow rate through short tube orifices using alternative refrigerants. The generalized correlations for two-phase and subcooled inlet conditions are separately derived from a power law form of dimensionless parameters generated by the Buckingham Pi theorem. The database for the present correlation includes extensive experimental data for R12, R22, R134a, R407C, R410A, and R502 obtained from the open literature. For subcooled inlet conditions at the short tube entrance, the correlation yields an average deviation of 0.3% and a standard deviation of 6.1% based on the present database, while for two-phase inlet conditons it predicts the database with an average deviation of 0.2% and a standard deviation of 5.0%. The relative deviations of the predictions using the present correlations for two-phase and subcooled inlet conditions range from −21% to 18%.     

Flow-boiling of R22, R134a, R507, R404A and R410A inside a smooth horizontal tube

Flow boiling heat transfer coefficients of R22, R134a, R507, R404A and R410A inside a smooth horizontal tube (6 mm I.D., 6 m length) were measured at a refrigerant mass flux of about 360 kg/m² s varying the evaporating pressure within the range 3–12 bar, with heat fluxes within the range 11–21 kW/m². The experimental data are discussed in terms of the heat transfer coefficients as a function of the vapour quality. The experimental results clearly show that the heat transfer coefficients of R134a are always higher than those pertaining to R22 (from a minimum of +6 to a maximum of +45%).     

R134a/R600a混合制冷剂应用于大型空气源热泵的性能研究

R134a作为当前主要的R22替代制冷剂,在应用于空气源冷水(热泵)机组,尤其是在热泵运行时会出现能效降低、容易结霜等问题。本研究尝试在R134a的大型螺杆式空气源热泵机组中混合少量R600a来改善机组性能。通过对混合制冷剂物性计算、理论循环性能计算和机组试验,表明添加R600a后的混合制冷剂能显著改善热泵机组的运行性能,并有效提高机组运行可靠性。同时,虽然R600a具有可燃性,但是对于运行时置于室外,介质为水且添加比例不高的空气源热泵机组,这是一个简单、安全、可行的改进方案。