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。     

R22,R407C和R410A热泵专用涡旋式压缩机研究

分析多种热泵制冷剂物理性质,并对热泵用涡旋式压缩机运行特性进行分析。采用新设计的热泵专用涡旋式压缩机进行R22,R407C与R410A性能测试,结果表明:R410A和R407C制冷剂均可以替代R22制冷剂在热泵系统中使用;R410A与R22在制热能力、排气温度及运行范围方面相近;R407C的制热能力高于R22和R410A,运行范围相对较宽。     

应用于热泵热水器的工质性能对比研究

从热泵热水器的原理和基本理论循环出发，分别对R22、R134a、R407C和R417a四种工质进行理论计算和对比分析，以便对热泵热水器的设计提供一定的参考。结果表明，四种工质中R134a和R417a最具推广价值，其结果还有待实验进行进一步论证。     

应用于高温烘干热泵领域涡旋压缩机的研究

本文介绍了高温烘干热泵原理,并根据应用特点及压缩机结构分析,提出普通涡旋压缩机应用于高温烘干热泵的结构优化,主要包括改进涡旋型线、电机和排气结构等方面。对比分析优化前后涡旋压缩机的制热能力、制热能效等试验结果,得出结论:两者在AHRI工况制热性能相近,但在高温烘干热泵工况下,高温烘干热泵专用涡旋机制热COP提升4. 5%。此外,笔者还对高温烘干热泵领域环保制冷剂替换加以研究,分析R134a与R513A在多个工况下的测试结果。综合分析结果显示两种制冷剂表现能力相当,R513A制冷剂GWP低于R134a 56%,有利于环保制冷剂替换。     

R515B在中高温热泵系统中的性能研究

对低GWP制冷剂R515B在双螺杆单级蒸汽压缩式热泵系统中的性能进行了研究。通过实验对比研究R515B直接替换R134a时系统的性能变化,结果表明：R515B的制热量比R134a降低27%左右,消耗功率比R134a降低约28%,制热COP比R134a平均提高1%,排气温度降比R134a低约15℃。同时建立热泵系统仿真模型,预测R515B在较高冷凝器出水温度下热泵系统的性能,结果表明：R515B具有优良的热力学性能和循环性能,在采用单级蒸汽压缩循环的中高温热泵系统中可实现88℃以下的高冷凝器出水温度。     

HCFC22替代用制冷剂混合物性能

本文将14种由R32、R125、R134a、R152a、R290（丙烷）和R1270（丙烯）等构成的制冷剂混合物在试验热泵上进行试验,以替代家用空调器中常和的HCFC22。该热泵能力为3．5kW,其蒸发器和冷凝器以不涂为传热介质（HTF）,并采和逆流型。所有试验中的HTF温度均固定在ARI试验工况A的数值。试验结果表明：由R32、R125和R134a构成的三元制冷剂混合物给出的性能系数（COP）和能力比HCFC22大4－5％。在其同时,由R125、R1134a和R152a构成的三元制冷剂混合物的COP和能力均低于HCFC22。R32／R134a二元制冷剂混合物的COP比HCFC22高7％,而R290／R134a二元共沸制冷剂的COP和能力均提高3－4％。所试验的制冷剂混合物压缩机排气温度均比HCFC22低得多,表明制冷剂事物系统可靠性和寿命均更高。最后,采用吸气一液体热交换器（SLHX）的试验结果表明,SLHX在用于空调器时须特别注意,因为其影响随制冷剂而定。     

R32/R134a和R407C用于变浓度热泵系统的实验

为了解决R32/R134a应用于变浓度热泵系统存在的排气温度过高问题,提出使用三元混合工质R407C用于该系统中.以R32/R134a和R407C作为工质在变浓度容量调节热泵系统中进行了吸气压力不变时的变浓度实验.实验结果表明,R407C在本系统中变浓度范围低于R32/R134a,但R407C的排气温度和耗功均低于R32/R134a,具有良好的变浓度调节潜力.     

R1234yf热泵技术综述与潜力分析

为了满足逐步严苛的环保法规要求,R1234yf成为车用热泵制冷剂R134a的热门替代制冷剂之一。本文对R1234yf热泵技术的研究进行了综述与分析,其GWP<1,各方面性质均符合车用热泵系统的工作需求。在传热效果上,R1234yf的沸腾传热性能略优于R134a,且冷凝过程压降比R134a低5%~10%,优于R134a系统。在诸多R1234yf和R134a系统的仿真和实验研究中,R1234yf热泵性能略低于R134a,但可以通过优化零部件、强化补气、改善工况等方式使其与R134a十分接近甚至超越。R1234yf低压饱和压力比R134a高约15%,可以适配更高的压缩机转速,低温下制热性能比R134a更好,且较低的压缩机排气温度使系统工作更为稳定,强化补气的效果也优于R134a。因此,R1234yf在车用热泵中具有较好的工作性能和发展前景,可以作为R134a的替代制冷剂。     

低温装置用R502替代工质的性能分析

本文对替代低温装置制冷剂R502的混合工质(如R404a、R507、R407a、R407b、R407c)进行了热力计算和循环分析,结果表明R407a、R407b、R407c可作为R502的替代工质,且比R404a和R507具有明显的节能效果。     

冷冻冷藏用制冷剂R404A的替代品对比分析

基于现有的R404A涡旋式压缩机,模拟分别采用R404A,R407A,R407F,R134a和R1234ze制冷剂时的压缩机性能,计算5种制冷剂系统的理论循环COP,并对各典型工况进行对比分析。计算结果表明,R407A和R407F可直接应用于R404A压缩机,而R134a和R1234ze替代R404A时压缩机设计变更较大,4种制冷剂系统能效均较R404A系统有较大提高。     

制冷剂R32特性及其用于空气源热泵热水器的理论循环分析

介绍R32,R22和R407C以及R410A四种制冷剂的流动特性和热力学特性,并对采用这4种制冷剂的空气源热泵热水器进行理论循环分析。从计算结果可以看出,与采用其他3种制冷剂的系统对比,采用R32制冷剂的系统具有较低的压缩比,较高的理论COP以及容积制热量;在当前阶段,R32是用于空气源热泵热水器的一种较好的制冷剂。     

采用替代工质的风冷热泵机组性能试验研究

近年来，我国风冷热泵空调技术的应用方兴未艾，风冷热泵由于其自身的优点，得到了制冷行业的重视。本文以搬2、R134a、R407C及R404A为工质，运用试验研究的方法，对热泵系统在冬季标准工况下的制热量及耗功进行测试和比较，可为风冷热泵系统中替代工质的选用，提供详细的实测数据和具体的设计准则。     

Modelling of reciprocating and scroll compressors

This paper presents simple and thermodynamically realistic models of two types of compressors widely used in domestic heat pumps (reciprocating and scroll compressors). These models calculate the mass flow rate of refrigerant and the power consumption from the knowledge of operating conditions and parameters. Some of these parameters may be found in the technical datasheets of compressors whereas others are determined in such a way that the calculated mass flow rate and electrical power match those given in these datasheets.The two models have been tested on five reciprocating compressors and five scroll compressors. This study has been limited to compressors with a maximum electrical power of 10 kW and for the following operating conditions: evaporating temperatures ranging from −20 to 15 °C and condensing temperatures ranging from 15 to 60 °C.The average discrepancies on mass flow rate and power for reciprocating compressors are 1.10 and 1.69% (for different refrigerants: R134a, R404A, R22, R12 and R407C). For scroll compressors, the average discrepancies on mass flow rate and power are 2.42 and 1.04% (for different refrigerants: R134a, R404A, R407C and R22).     

Refrigeration system performance using liquid-suction heat exchangersPerformance d''un système frigorifique utilisant des échangeurs liquide-vapeur à l''aspiration

Heat transfer devices are provided in many refrigeration systems to exchange energy between the cool gaseous refrigerant leaving the evaporator and warm liquid refrigerant exiting the condenser. These liquid-suction or suction-line heat exchangers can, in some cases, yield improved system performance while in other cases they degrade system performance. Although previous researchers have investigated performance of liquid-suction heat exchangers, this study can be distinguished from the previous studies in three ways. First, this paper identifies a new dimensionless group to correlate performance impacts attributable to liquid-suction heat exchangers. Second, the paper extends previous analyses to include new refrigerants. Third, the analysis includes the impact of pressure drops through the liquid-suction heat exchanger on system performance. It is shown that reliance on simplified analysis techniques can lead to inaccurate conclusions regarding the impact of liquid-suction heat exchangers on refrigeration system performance. From detailed analyses, it can be concluded that liquid-suction heat exchangers that have a minimal pressure loss on the low pressure side are useful for systems using R507A, R134a, R12, R404A, R290, R407C, R600, and R410A. The liquid-suction heat exchanger is detrimental to system performance in systems using R22, R32, and R717.     

一种R410A替代制冷剂的特性及应用前景分析

目前家用空调器R22的替代制冷剂，主要是R407C和R410A。由于这些制冷剂的专利权都在国外，且价格高昂，为此，国内浙江化工研究院开发出一种可替代R410A，且部分性能优于R410A的新型环保制冷剂。受该单位委托，笔者所在公司对该制冷剂进行了实机测试分析。     

Influence of the expansion device on the performance of a heat pump using R407C under a range of charging conditions

The objective of this study is to investigate the effects of the expansion device on the performance of a water-to-water heat pump using R407C, which has been considered as one of the alternative refrigerants to replace R22 with “soft-optimization”, at various charging conditions. The heat pump applying the expansion devices of a capillary tube and an EEV was tested by varying refrigerant charge amount from −20% to +20% of full charge and changing water temperature entering the condenser from 30 °C to 42 °C, while maintaining water temperature entering the evaporator at 25 °C. The R22 capillary tube system is utilized as a baseline unit for the performance comparison with the R407C system. The performance of the capillary tube system is more sensitive to off-design charge than that of the EEV system. As the refrigerant charge deviates from the full charge, the R407C EEV system shows a much lower degradation of capacity and COP as compared to the R22 and R407C capillary tube systems due to an optimum control of superheat by electronically adjusting the EEV opening. In addition, the R407C EEV system shows more a stable compressor discharge temperature at off-design charge than the R407C capillary tube system.     

Flow condensation heat transfer coefficients of R22, R134a, R407C, and R410A inside plain and microfin tubes

Flow condensation heat transfer coefficients (HTCs) of R22, R134a, R407C, and R410A inside horizontal plain and microfin tubes of 9.52 mm outside diameter and 1 m length were measured at the condensation temperature of 40 °C with mass fluxes of 100, 200, and 300 kg m⁻² s⁻¹ and a heat flux of 7.7–7.9 kW m⁻². For a plain tube, HTCs of R134a and R410A were similar to those of R22 while HTCs of R407C are 11–15% lower than those of R22. For a microfin tube, HTCs of R134a were similar to those of R22 while HTCs of R407C and R410A were 23–53% and 10–21% lower than those of R22. For a plain tube, our correlation agreed well with the present data for all refrigerants exhibiting a mean deviation of 11.6%. Finally, HTCs of a microfin tube were 2–3 times higher than those of a plain tube and the heat transfer enhancement factor decreased as the mass flux increased for all refrigerants tested.     

The surface tension of HFC refrigerants and mixtures

The surface tension of the refrigerants R32, R125, R134a, R143a and R152a, as well as the binary refrigerant mixtures R32-R125, R32-R134a, R125-R134a, R125-R143a, R125- R152a, R143a-R134a and R134a-R152a, and the commercially available ternary mixtures R404A and R407C was measured across the temperature range from −50 to 60°C using a measuring unit based on the capillary rise method. Different formulations for calculation of the surface tension of the binary and ternary mixtures on the basis of the surface tension of the pure refrigerants were tested. With an approach based on mass proportions in the mixture, a good correspondence between the measured and calculated values was achieved.