共查询到19条相似文献,搜索用时 171 毫秒
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本文介绍了我国家用空调器行业HCFCs制冷剂淘汰计划并说明研究R32作为R410A替代制冷剂的必性。比较了R32和R410A制冷剂的特性及替代可行性。以KFR-25GW/Bp变频空调器为对象,实机测试R32和R410A在相同空调系统中的空调器性能。以便给国内家用空调器行业选择使用R32制冷剂提供有益的参考。 相似文献
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本文阐述了以氟里昂22为制冷剂的小型风冷式毛细管节流空调器(以下简称空调器)在制冷状态下,利用制冷潜热量(蒸发器上析出凝露水冷量)对毛细管节流前冷凝器出口侧的液态制冷剂进行冷却处理,以提高空调器的制冷系数ε和能效比EER的原理和方法,同时对相关问题作一些说明. 相似文献
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为了解 R32 和 R410A 制冷剂应用于空气源热泵热水器时的性能优劣,采用同轴套管换热器与空调室外机组相匹配,使用电子膨胀阀作为节流装置,在国标GB/T 23137-2008 规定下实验测试 R32 和R410A 在同一套空气源一次加热式热泵热水器样机上的性能.实验结果表明,R32 的充注量仅为 R410A 充注量的74%左右;在各种实验条件下,R32 空气源热泵热水器的能效比不低于 R410A 系统;在3℃低温环境下,R32 样机的性能系数提高31.1%,但排气温度达到101.9℃.不利于 R32 制冷剂在低温条件下的应用;因容积制热量较大,在相同设计能力下 R32 压缩机的排气量可以比 R410A 系统降低4.5%. 相似文献
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《制冷与空调(北京)》2017,(2)
对R32窗式空调器的性能进行试验研究,调试系统配置,并与原R410A系统进行对比。试验结果表明,在额定制冷工况下,与R410A系统相比,R32系统的制冷量提高2.5%,能效比提高5.5%,系统最优充注量降低20.5%,排气温度提高9℃。同时,R32系统的最优毛细管长度比R410A系统更长。 相似文献
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《制冷与空调(北京)》2020,(11)
准确预测毛细管内两相流制冷剂的压降是提高毛细管分流精度的基础,而高精度的毛细管内制冷剂两相流摩擦因子关联式又是准确预测毛细管压降的关键。本文拟合得到毛细管内R410A两相流摩擦因子关联式,并给出基于近似积分的毛细管压降计算模型。试验验证表明:基于Blasius公式拟合的毛细管内R410A两相流摩擦因子关联式的平均预测误差为±5.3%,95%的数据点的预测误差在±20%以内,而基于本文提出的毛细管内R410A两相流摩擦因子关联式的压降计算结果与试验数据的误差在±12%以内,平均误差在±5%以内,相比Blasius公式具有更高的计算精度。 相似文献
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鉴于环境问题的日益突出,各国均开展了 R22制冷剂的替代工作,高效、环保的 R410A 冷媒,已成为业内公认的 R22制冷剂的良好替代物,但空调制冷压缩机要想使用 R410A 替代传统的 R2制冷剂,必须对压缩机结构等多方面进行重新优化设计,才能满足 R410A 制冷剂特性的要求,同时达到高效节能目的。结合实际产品对 R410A 压缩机从涡旋齿结构、壳体结构、润滑油的选择与油路设计等多个方面进行了优化设计,该设计能有效提高压缩机能效比与工作可靠性,为高能效直流变频涡旋压缩的设计提供了参考依据。 相似文献
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王磊 《制冷与空调(北京)》2014,(8):67-70
基于制冷量为12 kW的风管送风式空调(热泵)机组进行试验研究,分析节流位置、工况等因素对长连接管制冷剂追加量的影响,得出9.52 mm液管和15.88 mm气管条件下R410A制冷剂追加量的参考值。研究发现,对于单冷型空调器,节流位置会对长连接管的制冷剂追加量产生较大影响,室内机节流时的追加量大于室外机节流;而对于热泵型空调器,节流位置对长连接管制冷剂追加量的影响较小。 相似文献
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The objective of this study is to present test results and to develop a dimensionless correlation on the basis of the experimental data of adiabatic capillary tubes for R22 and its alternatives, R407C (R32/125/134a, 23/25/52 wt.%) and R410A (R32/125, 50/50 wt.%). Several capillary tubes with different length and inner diameter were selected as test sections. Mass flow rate through the capillary tube was measured for several condensing temperatures and various degrees of subcooling at the inlet of each capillary tube. Experimental conditions for the condensing temperatures were selected as 40, 45 and 50°C, and the degrees of subcooling were adjusted to 1.5, 5 and 10°C. Mass flow rates of R407C and R410A were compared with those of R22 for the same test conditions. The results for straight capillary tubes were also compared with those of coiled capillary tubes. A new correlation based on Buckingham π theorem to predict the mass flow rate through the capillary tubes was presented based on extensive experimental data for R22, R407C and R410A. Dimensionless parameters were chosen considering the effects of tube geometry, capillary tube inlet conditions, and refrigerant properties. Dimensionless correlation predicted experimental data within relative deviations ranging from −12% to +12% for every test condition for R22, R407C and R410A. The predictions by the developed correlation were in good agreement with the results in the open literature. 相似文献
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The capillary tube is often served as an expansion device in small refrigeration and air-conditioning systems. In this paper, a generalized correlation for predicting the refrigerant mass flow rate through the adiabatic capillary tube is developed with approximate analytic solutions based on the extensive data for R12, R22, R134a, R290, R600a, R410A, R407C, and R404A, in which a homogeneous equilibrium model for two-phase flow is employed, and there is a subcooled liquid or saturated two-phase mixture at the inlet of the capillary tubes. The collected database about capillary tubes covers the inner diameter from 0.5 mm to 2 mm, the tube length from 0.5 m to 5 m, the condensing temperature from 20 °C to 60 °C, the subcooling from 0 °C to 20 °C, and the quality from 0 to 0.3 at the inlet. Assessments for the correlation are made with some experimental data for R12, R22, R134a, R290, R407C, R410A, and R404A obtained from the open literature and some existing correlations based on the experimental database also. The present correlation yields an average deviation of −0.83% and a standard deviation of 9.02% from the database. 相似文献
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This paper presents a new method to obtain generalized dimensionless correlation of refrigerant mass flow rates through adiabatic capillary tubes and short tube orifices. The dimensionless Pi groups were derived from the homogeneous equilibrium model, which is available for different refrigerants entering adiabatic capillary tubes or short tube orifices as the subcooled liquid, two-phase mixture, or supercritical fluid. To mitigate the potential over-fitting risk in neural network, a new “local” power-law correlation reformed from the homogeneous equilibrium model was proposed and compared with the conventional “global” power-law correlation and recently developed neural network model. About 2000 sets of experimental mass flow rate data of R12, R22, R134a, R404A, R407C, R410A, R600a and CO2 (R744) in the open literature covering capillary and short tube geometries, subcritical and supercritical inlet conditions were collected for the model development. The comparison between the recommended six-coefficient correlation and experimental data reports 0.80% average and 8.98% standard deviations, which is comparable with the previously developed neural network and much better than the “global” power-law correlation. 相似文献
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In this paper, pressure drop through a capillary tube is modeled in an attempt to predict the size of capillary tubes used in residential air conditioners and also to provide simple correlating equations for practicing engineers. Stoecker's basic model was modified with the consideration of various effects due to subcooling, area contraction, different equations for viscosity and friction factor, and finally mixture effect. McAdams' equation for the two-phase viscosity and Stoecker's equation for the friction factor yielded the best results among various equations. With these equations, the modified model yielded the performance data that are comparable to those in the ASHRAE handbook. After the model was validated with experimental data for CFC12, HFC134a, HCFC22, and R407C, performance data were generated for HCFC22 and its alternatives, HFC134a, R407C, and R410A under the following conditions: condensing temperature; 40, 45, 50, 55°C, subcooling; 0, 2.5, 5°C, capillary tube diameter; 1.2–2.4 mm, mass flow rate; 5–50 g/s. These data showed that the capillary tube length varies uniformly with the changes in condensing temperature and subcooling. Finally, a regression analysis was performed to determine the dependence of mass flow rate on the length and diameter of a capillary tube, condensing temperature, and subcooling. Thus determined simple practical equations yielded a mean deviation of 2.4% for 1488 data obtained for two pure and two mixed refrigerants examined in this study. 相似文献
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Chasik Park Sunil Lee Hoon Kang Yongchan Kim 《International Journal of Refrigeration》2007,30(7):1168-1175
Air-conditioners use spirally coiled capillary tubes as an expansion device to enhance compactness of the unit. However, most empirical correlations for predicting refrigerant flow rate through capillary tubes were developed for straight capillary tubes without consideration of coiled effects. The objectives of this study are to investigate the flow characteristics of the coiled capillary tubes and to develop a generalized correlation for the mass flow rate through the coiled capillary tubes. The mass flow rate of R22 through the coiled capillary tubes and straight capillary tubes was measured for various operating conditions and tube geometries. The mass flow rates of the coiled capillary tubes decreased by 5–16% more than those of the straight capillary tubes at the same operating conditions. A generalized correlation for predicting refrigerant mass flow rate through coiled capillary tubes was developed by introducing the parameter of capillary equivalent length. The present correlation showed good predictions with the present database for R22, R407C and R410A in the straight and coiled capillary tubes, yielding average and standard deviations of 0.24% and 4.4%, respectively. 相似文献
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A capillary tube is a common expansion device widely used in small-scale refrigeration and air-conditioning systems. A generalized correlation of refrigerant mass flow rate through adiabatic capillary tubes covering both subcooled and two-phase inlet conditions is expected for multiple purposes. Based on the homogeneous equilibrium flow model, a new group of dimensionless parameters has been proposed. To express the nonlinear relationship between the mass flow rate and the associated parameters, the multi-layer perceptron neural network is employed as a universal function approximator. Simulated data from a validated homogeneous equilibrium model are used for the neural network training and testing. A 5-6-1 network trained with the simulated data of R600a and R407C shows good generality in predicting the simulated data of R12, R22, R134a, R290, R410A, and R404A. Also, the deviations between the trained neural network and the experimental data from the open literature fall into ±10%. 相似文献
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This paper presents a modified dimensionless neural network correlation of refrigerant mass flow rates through adiabatic capillary tubes and short tube orifices. In particular, CO2 transcritical flow is taken into account. The definition of neural network input and output dimensionless parameters is grounded on the homogeneous equilibrium model and extended to supercritical inlet conditions. 2000 sets of experimental mass flow-rate data of R12, R22, R134a, R404A, R407C, R410A, R600a and CO2 (R744) in the open literature covering capillary and short tube geometries, subcritical and supercritical inlet conditions are collected for neural network training and testing. The comparison between the trained neural network and experimental data reports 0.65% average and 8.2% standard deviations; 85% data fall into ±10% error band. Particularly for CO2, the average and standard deviations are −2.5% and 6.0%, respectively. 90% data fall into ±10% error band. 相似文献
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Pronounced hydrodynamic and thermodynamic non-equilibrium exist in the flow of refrigerant through a short tube orifice under typical operating conditions. A non-equilibrium two-fluid model (TFM) for refrigerant two-phase critical flow inside the short tube orifice is developed. Both inter-phase velocity slip and inter-phase temperature difference are taken into account in the model. The mass flow rate, the two-phase velocity and temperature distributions in a short tube orifice are simulated. Comparisons among the experimental data of refrigerants R134a, R12, R22, R410A and R407C flowing through short tubes, the predictions by the TFM and by the homogeneous equilibrium model (HEM) show that the TFM gives acceptable predictions with the deviations of ±20%, while the HEM underestimates the flow rate by 20% or so. 相似文献
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Diogo L. da Silva Christian J.L. Hermes Cláudio Melo Joaquim M. Gonçalves Gustavo C. Weber 《International Journal of Refrigeration》2009,32(5):978-987
This paper advances a study of the transcritical expansion of carbon dioxide (R-744, CO2) through adiabatic capillary tubes. The influence of both operating conditions (inlet and exit pressures, inlet temperature) and tube geometry (capillary diameter and tube length) on the CO2 mass flow rate was experimentally evaluated using a purpose-built testing facility with a strict control of the measured variables. A dimensionless correlation to predict the refrigerant mass flow rate as a function of tube geometry and operating conditions was developed. In addition, a theoretical model was put forward based on the mass, energy and momentum conservation principles. The model results were compared with experimental data, when it was found that the model predicts 95% of the measured refrigerant mass flow rate within an error band of ±10%. The model was also employed to advance the knowledge about the transcritical carbon dioxide flow through adiabatic capillary tubes. 相似文献