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

Jia, Xiaohan; Zhang, Chao; Pu, L; Guo, Baolin; Peng, Xueyuan

doi:10.1016/j.ijrefrig.2010.12.005

Cited by 43 publications

(14 citation statements)

References 20 publications

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“…Regarding new components, the CO 2 expander concept is still under maturation, few experimental works were found in the literature, such as the experimental tests with a rotary vane expander of Jia et al [4] and with a two-rolling piston expander of Hu et al [5]. However, great progress was achieved in the last decade regarding the ejector technology; it was already implemented in many plants all over the world, where the energy improvements were experimentally demonstrated [6].…”

Section: Introductionmentioning

confidence: 99%

CO2 with Mechanical Subcooling vs. CO2 Cascade Cycles for Medium Temperature Commercial Refrigeration Applications Thermodynamic Analysis

Nebot‐Andrés¹,

Llopis²,

Sánchez³

et al. 2017

Applied Sciences

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Abstract:A recent trend to spread the use of CO 2 refrigeration cycles in warm regions of the world is to combine a CO 2 cycle with another one using a high performance refrigerant. Two alternatives are being considered: cascade and mechanical subcooling systems. Both respond to a similar configuration of the refrigeration cycle, they being based on the use of two compressors and same number of heat exchangers. However, the compressor, heat exchanger sizes and energy performance differ a lot between them. This work, using experimental relations for CO 2 and R1234yf semi-hermetic compressors analyzes in depth both alternatives under the warm climate of Spain. In general, it was concluded that the CO 2 refrigeration solution with mechanical subcooling would cover all the conditions with high overall energy efficiency, thus it being recommended for further extension of the CO 2 refrigeration applications.

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Section: Introductionmentioning

confidence: 99%

CO2 with Mechanical Subcooling vs. CO2 Cascade Cycles for Medium Temperature Commercial Refrigeration Applications Thermodynamic Analysis

Nebot‐Andrés¹,

Llopis²,

Sánchez³

et al. 2017

Applied Sciences

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“…Li et al [14] experimentally found that their developed rolling-piston expander prototype can improve the COP of the system by at least 10%. Jia et al [15] represented that a maximum COP improvement of 27.2% can be achieved by the use of the vane expander prototype.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Analysis of Double-Stage Compression Transcritical CO2 Refrigeration Cycles with an Expander

Zhang¹,

Tong²,

Wang³

2015

Entropy

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Four different double-compression CO2 transcritical refrigeration cycles are studied: double-compression external intercooler cycle (DCEI), double-compression external intercooler cycle with an expander (DCEIE), double-compression flash intercooler cycle (DCFI), double-compression flash intercooler cycle with an expander (DCFIE). The results showed that the optimum gas cooler pressure and optimum intermediate pressure of the flash intercooler cycles are lower than that of the external intercooler cycle. The use of an expander in the DCEI cycle leads to a decrease of the optimum gas cooler pressure and little variation of the optimum intermediate pressure. However, the replacement of the throttle valve with an expander in the DCFI cycle results in little variation of the optimal gas cooler pressure and an increase of the optimum intermediate pressure. The DCFI cycle outperforms the DCEI cycle under all the chosen operating conditions. The DCEIE cycle outperforms the DCFIE cycle when the evaporating temperature exceeds 0 °C or the gas cooler outlet temperature surpasses 35 °C. When the gas cooler exit temperature varies from 32 °C to 48 °C, the DCEI cycle, DCEIE cycle, DCFI cycle and DCFIE cycle yield averaged 4.6%, 29.2%, 12.9% and 22.3% COP improvement, respectively, over the basic cycle.

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“…19 Rotary vane expander, which has similar structure with RVC, is usually used to replace the throttle valve to improve efficiency in refrigeration and air-conditioning fields, especially in CO 2 refrigeration systems. [20][21][22] Several studies [23][24][25][26][27][28][29] on rotary vane expanders were conducted.…”

Section: Introductionmentioning

confidence: 99%

Profile design for the cylinder of a double-acting rotary vane compressor

Song

Zeng

Zhou

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part C:

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Inner wall profile of the cylinder in a rotary vane compressor (RVC), which influences the motion characteristics of vanes, suction volume, friction characteristic, etc., plays an important role in the performance of the compressor. This work mainly aims at the profile design of a new cylinder for a double-acting RVC with harmonic profile cylinder on the basis of not changing integrate size. According to the relation between cylinder profile and vane motion characteristics, a method for the cylinder profile design is proposed in this paper. With an assumed vane motion, equations of the cylinder profile, cell volume of the compressor as well as pressure angles between vanes and cylinder inner wall are constructed preliminarily. And then through adjusting parameters and optimization with an independently developed procedure, a new cylinder with the so-called combined profile is obtained. Theoretical analysis of the cell volume variations and the pressure angles between vanes and cylinder are conducted. The results show that there is neither rigid impulse nor soft impulse between vanes and cylinder due to the vane continuous motion including displacement, velocity and acceleration. And the pressure angles between vane and cylinder and working volume of the compressor with the new profile cylinder are superior to harmonic profile cylinder, which is useful for the reduction of friction power in the operation of compressor. Experiments show that the cooling capacity and COP of the test refrigeration cycle with the proposed combined profile cylinder is higher than the compressor with harmonic profile cylinder. And the volumetric efficiency and isentropic efficiency of the compressor with combined profile cylinder have better performance. This method can be applied to the design of the cylinder for multiple-acting rotary vane compressors, rotary vane expanders and vane pumps.

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

Cited by 43 publications

References 20 publications

CO2 with Mechanical Subcooling vs. CO2 Cascade Cycles for Medium Temperature Commercial Refrigeration Applications Thermodynamic Analysis

CO2 with Mechanical Subcooling vs. CO2 Cascade Cycles for Medium Temperature Commercial Refrigeration Applications Thermodynamic Analysis

Thermodynamic Analysis of Double-Stage Compression Transcritical CO2 Refrigeration Cycles with an Expander

Profile design for the cylinder of a double-acting rotary vane compressor

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