Improved rotary vane expander for trans-critical CO2 cycle by introducing high-pressure gas into the vane slots

Abstract The loss of contact between the vane tip and cylinder wall was proven to cause a serious leakage and inefficient operation of the rotary vane expander, which was developed to replace the throttling valve in the trans-critical CO2 refrigeration system. An improved structure was suggested by introducing high-pressure gas into the vane slots. This paper presents the experimental investigation of the improved prototype expander. By comparing the improved prototype with the original, focusing on the expander performance and the p–θ diagram as well as the vane movement, the effects of introducing high-pressure gas into the slots on the thermodynamic processes and performance were analyzed. The results showed that, by introducing the high-pressure gas into the vane slots, the volumetric efficiency was increased from 17% to 35%, and the isentropic efficiency improved from 15% to 45%, resulting in a maximum COP improvement of 27.2% compared to the throttling cycle under the same working conditions.

[1]  Eckhard A. Groll,et al.  Piston-cylinder work producing expansion device in a transcritical carbon dioxide cycle. Part I: experimental investigation , 2005 .

[2]  Xueyuan Peng,et al.  Study of a Rotary Vane Expander for the Transcritical CO2 Cycle—Part I: Experimental Investigation , 2009 .

[3]  Bo Zhang,et al.  Study of a Rotary Vane Expander for the Transcritical CO2 Cycle—Part II: Theoretical Modeling , 2009 .

[4]  Wei Wang,et al.  Study on expansion power recovery in CO2 trans-critical cycle , 2010 .

[5]  Kim Tiow Ooi,et al.  Design analysis of the novel revolving vane expander in a transcritical carbon dioxide refrigeration system. , 2010 .

[6]  Guan Haiqing,et al.  Some design features of CO2 swing piston expander , 2006 .

[7]  G. Lorentzen.  Revival of carbon dioxide as a refrigerant , 1994 .

[8]  Xueyuan Peng,et al.  Experimental investigation on the internal working process of a CO2 rotary vane expander , 2009 .

[9]  Eckhard A. Groll,et al.  Piston-cylinder work producing expansion device in a transcritical carbon dioxide cycle. Part II: theoretical model , 2005 .

[10]  S. D. Probert,et al.  Performances of multi-vane expanders , 1985 .

[11]  S. D. Probert,et al.  Multi-vane expander performance: Breathing characteristics , 1985 .

[12]  S. D. Probert,et al.  Multi-vane expanders: Geometry and vane kinematics , 1985 .

[13]  J. Pettersen,et al.  A new, efficient and environmentally benign system for car air-conditioning , 1993 .

[14]  W. E. Kraus,et al.  Integration of a three-stage expander into a CO2 refrigeration system , 2005 .

[15]  Pengcheng Shu,et al.  Development of a double acting free piston expander for power recovery in transcritical co2 cycle , 2007 .

[16]  Ma Yitai,et al.  The development of CO 2 expander technology in CO 2 transcritical cycles , 2003 .

[17]  O. Badr,et al.  Multi-vane expanders: Internal-leakage losses , 1985 .

[18]  Hua Tian,et al.  A Rolling Piston-Type Two-Phase Expander in the Transcritical CO2 Cycle , 2009 .

[19]  Guan Haiqing.  Research and Development of Rolling Piston Expander in CO_2 Transcritical Cycle--Experimental Part , 2004 .

[20]  S. D. Probert,et al.  Multi-Vane expanders as prime movers for low-grade energy organic Rankine-cycle engines , 1984 .

[21]  S. D. Probert,et al.  Multi-vane expanders: Vane dynamics and friction losses , 1985 .