共查询到19条相似文献,搜索用时 62 毫秒
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新型高效的跨临界二氧化碳汽车空调系统 总被引:1,自引:0,他引:1
随着技术成熟和工艺发展,二氧化碳汽车空调系统的主要零部件,如压缩机、换热器及节流阀,也逐渐多样化,涡漩式和变排量压缩机、高效换热器、系统控制技术的应用,使跨临界二氧化碳汽车空调系统的性能已优于HFC134a系统,作为下一代的汽车空调,二氧化碳系统得到越来越多的认同. 相似文献
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二氧化碳跨临界循环制冷的研究进展 总被引:1,自引:0,他引:1
给出了CO2跨临界制冷循环的典型流程和特点;对国内外针对超临界CO2特性的研究、CO2制冷循环的研究、CO2制冷设备的研究与开发以及CO2跨临界循环系统安全性与可靠性的研究现状等4个方面进行了综述,指出了二氧化碳跨临界循环制冷的发展趋势. 相似文献
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跨临界二氧化碳汽车空调系统的研究与分析 总被引:1,自引:0,他引:1
随温室效应日益加剧,二氧化碳制冷剂重新回到人们的视野,引起广泛关注。介绍了跨临界二氧化碳汽车空调系统的组成及热力循环模型,并阐述了系统主要部件压缩机、气体冷却器、蒸发器、节流机构工作性能的影响因素和研究发展方向。 相似文献
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二氧化碳跨临界压缩机研究进展 总被引:2,自引:0,他引:2
介绍CO2制冷剂跨临界循环的优势,回顾CO2压缩机的发展历史,对已开发的各种类型的CO2压缩机进行分析,总结CO2压缩机发展的关键技术。 相似文献
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CO2跨临界膨胀机的开发与实验研究 总被引:3,自引:0,他引:3
作为自然工质,CO2制冷系统越来越受到关注,然而目前CO2跨临界循环研究面临的最大问题是如何提高系统效率,使之能与普通工质循环竞争。为降低CO2跨临界循环的节流损失,开发膨胀机代替节流阀是研究的重要方向。文中给出开发CO2滚动活塞膨胀机的依据,以及在设计过程中需解决的吸气控制系统、泄漏和摩擦等问题采取的措施,同时建立CO2跨临界循环系统带膨胀机系统的实验装置,并对CO2滚动活塞膨胀机进行实验研究,发现膨胀机的输出功与负载有关,同时得出膨胀机的最高效率可达到32%以上,进一步的改进工作仍在进行。 相似文献
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二氧化碳跨临界循环制冷的开发与研究进展 总被引:1,自引:0,他引:1
由于近年来制冷剂对臭氧层的破坏和全球温室效应等环保问题日益突出,CO2作为理想的制冷剂开始重新得到重视。给出了CO2跨临界制冷循环的典型流程和特点;对国内外针对超临界CO2特性的、CO2制冷循环、CO2制冷设备的开发以及CO2跨临界循环系统安全性与可靠性等四个方面的研究现状进行了综述,指出了二氧化碳跨临界循环制冷今后的发展趋势。 相似文献
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Luca Cecchinato Manuel Chiarello Marco Corradi Ezio Fornasieri Silvia Minetto Paolo Stringari Claudio Zilio 《International Journal of Refrigeration》2009,32(5):1058-1067
The aim of this paper is the thermodynamic evaluation and optimisation of different two-stage transcritical carbon dioxide cycles. Five different cycles are studied: basic single-stage cycle, single-throttling with two-stage compression cycle, split cycle, phase separation cycle and single-stage cycle coupled with a gas cooling circuit. Each basic cycle is analysed for the effect of internal heat transfer between different streams of refrigerants. In the case of two-stage compression, intermediate cooling between the compressor stages is present. An analysis on the Plank cycle for intermediate pressure higher than critical one is performed. Each cycle is optimised with regards to energy performance, calculating the optimal values of both the upper and the intermediate pressures. In the case of split cycle, the ratio of the mass flow rate in the main stream to the one in the auxiliary stream is also optimised. 相似文献
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Two-stage transcritical carbon dioxide cycle optimisation: A theoretical and experimental analysis 总被引:3,自引:0,他引:3
Alberto Cavallini Luca Cecchinato Marco Corradi Ezio Fornasieri Claudio Zilio 《International Journal of Refrigeration》2005,28(8):1274-1283
The aim of this paper is to investigate, both experimentally and theoretically, the potential of improving the cycle efficiency through two stage compression with intermediate cooling, at operating conditions typical of air conditioning. The experimental set-up consists of two closed loop air circuits acting as heat sink and heat source for gas-cooler and evaporator, respectively. The tested refrigerating circuit includes two tube-and-fin heat exchangers as gas-cooler and evaporator, a back-pressure valve as throttling device and a double-stage semi-hermetic compound, two-piston, reciprocating compressor equipped with oil separator and intercooler. A full set of thermocouples, pressure transducers and flow-meters allows measurement of all the main parameters of the CO2 cycle, enabling to perform heat balance both air and refrigerant side. Tests were run at fixed evaporation pressure, evaporator outlet superheating and gas-cooler outlet temperature, varying the gas-cooler outlet pressure in the range 8–11 MPa. The optimal gas-cooler pressure for this application as well as the effect of the intercooler efficiency on the cycle performance were investigated.
A FORTRAN code for the simulation of an improved two-stage cycle was validated against the experimental results; a theoretical analysis performed with this code is proposed for optimisation and energy performance evaluation of such a cycle. 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
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Christian J.L. Hermes Diogo L. da Silva Cláudio Melo Joaquim M. Gonçalves Gustavo C. Weber 《International Journal of Refrigeration》2009,32(5):973-977
This paper outlines an algebraic model for simulating the transcritical expansion of carbon dioxide through adiabatic capillary tubes. The model was put forward based on the analytical solution of the momentum conservation equation assuming an isenthalpic expansion process. The theoretical model predictions were compared with 66 experimental data points covering different operating conditions and tube geometries. A good agreement between the experimental and calculated mass flow rates was achieved, with more than 94% of the data points lying within an error band of ±10%. 相似文献
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Diogo L. da SilvaAdriano F. Ronzoni Cláudio MeloChristian J.L. Hermes 《International Journal of Refrigeration》2011,34(4):834-843
An experimental and theoretical study of the diabatic flow of carbon dioxide through lateral capillary tube suction line heat exchangers is outlined. The influence of both operating conditions (capillary tube inlet and outlet pressures, capillary tube inlet temperature and suction line inlet temperature) and tube geometry (heat exchanger length and position, suction line diameter and capillary tube length) on the heat and mass flow rates was experimentally evaluated using a purpose-built testing facility. In total, 75 tests were carried out with heat fluxes spanning from 1 to 11 kW m−2 and refrigerant mass flow rates ranging from 12 to 26 kg h−1. In addition, the mathematical model of Hermes et al. (2008) was adapted to run with carbon dioxide as working fluid. The model was validated against experimental data, and a good agreement between the experimental and calculated mass flow rates was achieved with 85% and 98% of the data points being within ±5% and ±10% error bounds, respectively. 相似文献
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变频空调器压缩机图形法建模研究 总被引:9,自引:1,他引:8
通过把变频压缩机实际运行工况离散成无穷多个定速压缩机运行工况,采用图形法对压缩机性能曲线进行拟台,厂家提供的性能曲线表明拟合精度较高;在图形法拟合的基础上,借鉴成熟的对实际过热度进行修正的方法,建立了变步页空调器压缩机模型。 相似文献