R1234ze(E)/R32混合工质热泵系统性能的实验研究

低全球变暖潜能值(Global Warming Potential,GWP)制冷剂R1234ze(E)作为R410A较为理想的替代品而被关注。但是纯R1234ze(E)的热力学性能和传输特性并不出色。近期研究表明R1234ze(E)中混入R32成分可以有效提高其热力学性能。本文在空气源热泵测试实验系统中以R1234ze(E)/R32(质量配比为27%/73%,命名为L-41b,GWP为493)混合工质为研究对象,考察了R1234ze(E)和混合工质L-41b在实际热泵系统中的运行性能。与常规制冷工质R410A的运行性能在相同工况下进行了对比,在相对高温区中L-41b对R410A具有良好的替代性能。研究结果为R1234ze(E)及其与R32混合工质的产品设计开发提供了参考数据。     

R1234ze(E)在R134a离心式制冷压缩机中的直接替代研究

随着全球对环保要求的日益提高,以R1234yf、R1234ze(E)、R1233zd(E)等为代表的ODP为0且GWP较低的制冷剂得到广泛关注并应用。针对R134a离心式冷水机组,采用CFD数值方法,对采用R1234ze(E)直接替代的离心制冷压缩机进行了模拟,对机组性能进行了比较分析。结果表明：在同一转速下,当冷凝温度较小时,R1234ze(E)机组的制冷量和COP都小于R134a机组的,当冷凝温度较大时,R1234ze(E)机组的制冷量和COP都大于R134a机组的。当R134a机组与R1234ze(E)机组的蒸发温度、冷凝温度和制冷量都相同时,R1234ze(E)机组的COP比R134a机组的COP平均降低了约5.14%。     

新型制冷剂R1234ze(E)及其混合工质研究进展

低GWP值制冷剂R1234ze(E)(trans-1,3,3,3-tetrafluoropropene)作为R134a较为理想的替代品而被关注,但其单一成分的热力学性能和传输特性并不理想,在R1234ze(E)中混入R32成分可以有效改善其热力学性能。本文概述了低GWP值工质R1234ze(E)及其与R32混合物的热物性特征、传输特性及系统运行性能方面的研究现状,并与目前常用的制冷工质进行比较分析,指出R1234ze(E)与R32混合工质有望成为新型低GWP值替代工质。     

HFO-1234ze在空气源热泵热水器中 替代R417A、R22的研究

首先从热物性、ODP、GWP、工质毒性、可燃性方面对HFO-1234ze、R417A、R22三种制冷剂进行对比,并进行理论计算,初步分析HFO-1234ze制冷剂运用在空气源热泵热水器上的可行性。然后,在焓差法实验室内,对分别采用HFO-1234ze,R417A和R22作为制冷工质的空气源热泵热水器进行名义工况下的性能测试,对三种制冷剂的吸排气温度,吸排气压力,压缩机输入功率、制热量、性能系数进行对比分析。本文研究结果显示HFO-1234ze可以作为R417a与R22在热泵热水器中的替代制冷剂。此次研究为热泵热水器的工质选择提供参考。     

R1234ze(E)与R134a在冷水机组中的应用对比与探讨

介绍HFO类制冷剂R1234ze(E)与HFC类制冷剂R134a的基础特性,分别将这2种工质在螺杆式冷水机组上开展制冷循环性能试验,进行整机制冷量、降膜蒸发器传热性能、壳管式冷凝器传热性能及COP等方面的测试。试验结果表明:R1234ze(E)相比R134a样机制冷量有较大的衰减,蒸发和冷凝传热性能均有下降,而整机COP略有提升。指出后续需要针对R1234ze(E)性能衰减、传热能力下降等问题进行深入研究。     

HFO-1234ze与HFC-32混合制冷剂用于热泵热水器的实验研究

本文选用了NIST发行的REFPRO9.0制冷剂计算程序及KW2模型参数对混合制冷剂HFO-1234ze与HFC-32在不同配比下的热物性进行了模拟计算,并依据热泵热水器测试的标准工况,计算了不同配比下混合制冷剂的理论循环特性,分析得出了HFO-1234ze/HFC-32较为合适的配比。通过一次加热(即热式)热泵热水器实验台,对多种环境工况及不同进水温度进行性能测试,分别对R410A和混合制冷剂(HFO-1234ze与HFC-32配比0.3/0.7)在实验系统中的压缩机功率、系统性能系数、压缩机吸、排气压力和温度、冷凝器出水温度等参数进行了对比分析。结果表明:混合制冷剂(HFO-1234ze与HFC-32配比0.3/0.7)的压缩机功率和排气压力都低于R410A系统,而COP高于R410A系统,在标准工况下,分别为4.03和3.56,且在高于标准工况的环境温度情况下,混合制冷剂系统COP下降速率低于R410A系统,有利于热水器机组的安全稳定运行,在替代R410A系统方面具有可行性。     

R1234ze/HCs非共沸混合工质热泵系统循环性能分析

在热泵热水器名义工况下,本文建立了热泵系统循环热力学模型,利用EES程序对混合工质R1234ze/HCs及对应的纯工质热泵系统循环性能进行了对比分析。结果表明:R1234ze/R600在质量分数(20/80)和R1234ze/R600a在质量分数(40/60)存在最优配比,对应的最大制热COP_h分别为3. 41和3. 32,而R1234ze/R290则呈现单调下降趋势。R1234ze/R600(20/80)系统的制热COP_h比R1234ze/R600a(40/60)、R1234ze、R290、R600、R600a系统分别高2. 7%、17%、0. 09%、16. 3%和17. 8%,排气温度为76. 9℃,冷凝压力为0. 711 MPa,压比为6. 32,有望成为新型替代工质。     

基于氨工质的新型电动汽车空调系统性能研究

R134a制冷剂的GWP值较高,即将被淘汰,但采用何种制冷剂来替代R134a却还未明确。鉴于此,提出将氨这种天然制冷剂应用到电动汽车空调上,作为R134a的替代制冷剂,并对研究设计的氨工质电动汽车空调系统做了性能研究,研究表明:氨工质电动汽车空调系统理论COP随蒸发温度、过冷度的升高而增大,随冷凝温度、过热度的升高而降低;研究设计的氨工质电动汽车空调系统理论COP为4.09,与R1234yf理论COP相当,但经二次回路设计后氨比R1234yf安全可靠;相较于R152a,氨的GWP值更低,环保性更好;相较于CO2,氨的COP更高,节能性更好。     

替代R410A低GWP制冷剂R454B和R452B的特性研究

本文介绍了低GWP环保替代制冷剂R454B和R452B与现有行业内常用的R410A制冷剂的特性参数对比,并基于同一套压缩机测试系统,对比这两种制冷剂的制冷量和性能等参数测量结果的变化趋势。结果显示直接使用R454B制冷剂替换R410A将会平均降低约5.6%的制冷量,R452B平均降低约3%的制冷量。但在较低蒸发温度和较高冷凝温度的工况区域R454B/R452B制冷剂能够带来更高的能效优势,因此,依照实际应用差异能够为日后推动环保制冷剂直接替换和新系统的使用提供理论依据。     

不同工质的热泵热水器热力学性能分析

为了研究R22替代制冷剂R134A、R407C、R410A、R32、R290在热泵热水器中的热力学性能,设定冬季工况蒸发温度-10℃、冷凝温度65℃,夏季工况蒸发温度20℃、冷凝温度65℃,过冷度和过热度均为5℃。计算了不同工质系统在冬季和夏季工况的理论循环性能,对比分析了各系统的变工况特性。结果表明:R410A和R32的单位容积制热量较高,这有利于减小压缩机的功耗和体积;R290和R32的单位质量制热量较高,能够有效降低工质充注量,进而增加系统安全性。随着蒸发温度升高,各工质系统制热系数均不断增加;随着冷凝温度升高,各工质系统制热系数均不断降低;过热度变化对各工质系统制热系数影响很小,而过冷度增加可以提高各工质系统制热系数。对于6种工质热泵热水器系统,蒸发温度在冬季工况对R32系统制热系数影响最大,当蒸发温度由-14℃升至-6℃,R32系统制热系数提高21.8%,夏季工况蒸发温度对R22系统制热系数影响最大,当蒸发温度由16℃升至24℃,R22系统制热系数提高22.1%。对应于冬季工况和夏季工况,冷凝温度和过冷度变化对R410A系统制热系数影响最大。     

Viscosity of refrigerants R12, R113, and R114 and mixtures of R12 + R114 at high pressure

New viscosity measurements for the gaseous and supercritical state of the halogenated hydrocarbons R12, R113, and R114 and binary mixtures of R12 + R114 of different compositions are presented. The measurements were carried out at superheated and supercritical temperatures from 30 to 200° C and in the pressure range from 1 to 80 bar. Viscosity was measured with an oscillating-disk viscometer and the data obtained are relative to the viscosity of nitrogen. The estimated accuracy of the measured results is ±0.6%. The results obtained show that, at subcritical temperatures, the pressure effect on viscosity is negative. This anomalous behaviour is investigated in detail in this work. At atmospheric pressure the viscosity of gas mixtures is almost a linear function of their composition. At high pressure, the residual viscosities - ₀ of both the pure components and the mixtures were used to follow a single relationship versus the residual reduced density _r0.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

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.     

Viscosity of Gaseous R404A, R407C, R410A, and R507

This paper presents new measurements of the viscosity of gaseous R404A (52 wt% R143a, 44 wt% R125, 4 wt% R134a), R407C (23 wt% R32, 25 wt% R125, 52 wt% R143a), R410A (50 wt% R32, 50 wt% R125), and R507 (50 wt% R143a, 50 wt% R125). These mixtures are recommended as substitutes for the refrigerants R22, R502, and R13B1. Measurements were carried out in an oscillating-disk viscometer. The obtained values of the viscosity are relative to the viscosity of nitrogen. The experiments were performed at atmospheric pressure over the temperature range 297 to 403 K. and near the saturation line up to pressures of 0.6 P _crit. The estimated uncertainty of the reported viscosities are ±0.5% for the viscosities at atmospheric pressure and ± 1% along the saturation line, being limited by the accuracy of the available vapor pressure and density data. The experimental viscosities at atmospheric pressure are employed to determine the intermolecular potential parameters, and , which provide the optimum representation of the data with the aid of the extended law of corresponding states developed by Kestin et al. A comparison of the experimental viscosity data with the values calculated by REFPROP, both at atmospheric pressure and along the saturation line, is presented.     

R32替代R22的可行性探讨

从理论热工性能分析、环保、安全以及性能测试试验对比等角度,讨论制冷剂 R32 替代 R22 的优势,认为R32替代R22是可行的.同时,分析R32替代R22时存在的高排气压力和高排气温度以及安全性问题.基于目前的制冷技术以及R32本身的热力特性,只要能够通过采取一系列技术手段和安全措施解决这些问题,R32可以作为R22良好的过渡或替代制冷剂.     

R290与R404A在水平管内沸腾换热的压降研究

将R22的两种新型替代工质R290和R404A在光管和内螺纹管中的沸腾换热压降实验结果与Lockhart ＆ Martinelli压降计算关联式预测结果进行了比较，并依据工质R290和R404A在内螺纹管中的实验压降值对Lockhart ＆ Marlinelli压降计算关联式进行了修正。结果表明Lockhart ＆ Martinelli关联式对R404A在光管和内螺纹管的沸腾换热摩擦压降，均有良好的预测精度，平均偏差分别为-11．52％和-17．86％。Lockhart ＆ Martinelli关联式可以较好的预测R290在光管内的沸腾换热摩擦压降，平均偏差为-21．68％；经修正后的Lockhart ＆ Martinelli关联式可以较好的预测R290在在内螺纹管中的沸腾换热摩擦压降，Lockhart ＆ Martinelli关联式乘上修正系数2．06后的修正值与实验值偏差较小，平均偏差为2．37％。研究结果对R290和R404A蒸发器的工程设计及优化具有一定参考意义。     

Viscosity of R134a, R32, And R125 at Saturation

This paper reports the results of the measurement of the viscosity of R134a close to the saturation line in the vapor phase. The new measurements were carried out in a vibrating-wire viscometer specially constructed for the purpose, and the results have an accuracy of ±2%. In addition, the opportunity is taken to present a reevaluation of earlier measurements along the saturation line of the viscosity of R32 and R125. Improved equations of state for these fluids are now available and can be employed to generate improved values for the viscosity.     

冷藏车层叠式蒸发器应用R404A与R22和R134a的比较

采用分布参数法对层叠式蒸发器建立数学模型，并对蒸发器采用R404A，R22和R134a时的换热和流动性能进行模拟比较。结果表明，在空调工况范围内，新型中低温混合制冷剂R404A具有R134a换热性能好和R22压降小的特点，能够很好地适用于冷藏车系统空调侧层叠式蒸发器。     

新型混合制冷剂R1270/R152a/R13I1的理论研究

针对制冷剂R22的替代问题,提出了一种适用于空调等制冷设备的环保型混合制冷剂R1270/R152a/R13I1。基于Refprop8.0,对R1270/R152a/R13I1的基本热物理性质和制冷系统循环性能进行了分析,研究表明:在标准工况下,R1270/R152a/R13I1混合制冷剂的COP和单位容积制冷量均与R22相当,非常有利于直接灌注式替代;在变工况下,R1270/R152a/R13I1的滑移温度较小,性能优于R407C,单位容积制冷量与R407C和R22相当,是一种优良的R22替代物。     

在家用／商用空调中用R32替代R22的探索

在R22的替代工作进入实质性阶段,但国内外成熟替代品又尚不明朗之际,本文在分析国内外R22替代物的现状、存在的问题以及国际上对环保工质要求的新趋向的前提下,探索提出在家用／商用空凋中使用R32替代R22的设想,并从其热物理性质、环保特性、安全性、热工性能、市场可获得性等几个方面,与现有的R22替代物R410A,R290和R1234yf等进行比较,认为R32是一种兼顾减排、安全、节能和市场诸方面要求的、很有前景的R22替代制冷剂。     

Measurements of the thermal conductivity of liquid R32, R124, R125, and R141b

This paper reports measurements of the thermal conductivity of refrigerants R32, R124, R125, and R141b in the liquid phase. The measurements, covering a temperature range from 253 to 334 K and pressure up to 20 MPa, have been performed in a transient hotwire instrument employing two anodized tantalum wires. The uncertainty of the present thermal-conductivity data is estimated to be ±0.5%. The experimental data have been represented by polynomial functions of temperature and pressure for the purposes of interpolation. A comparison with other recent measurements is also included.