الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The Stirling cycle is regarded as one alternative to the compressive cooling cycle. The current study examines the performance of a beta Stirling refrigerator with a cylinder with different bores. Bores differ in terms of the diameters of the compression space and expansion space cylinder. The refrigerator comprises a twin shell and tube condenser, and evaporator. The evaporator and condenser tubes have an elliptical cross-section. The elliptical ratios in the evaporator and condenser (1, 0.75, 0.50, 0.25, 0.20) with a fixed cross-section area are compared. A wire mesh regenerator is used as the regenerator. The selection of the working fluid is helium.
The current work prepares a spreadsheet program to overcome the reversed Stirling refrigeration cycle. The suitable dimensions of the refrigerator to obtain a high cooling load are determined. The results recommended that using tubes with elliptical cross-sections in both evaporator and condenser enhances the COP of the refrigerator by about 33% (COP =1.3). Also, using tubes having elliptical cross-sections in both evaporator and condenser enhances the cooling load of the refrigerator by about 24% at a 0.2 elliptical ratio.
Furthermore, the use of different bores of refrigerator cylinders increases the cooling load of the refrigerator by about 25% when the expansion to compression bore ratio is 1.5.
Additionally, the use of different bores of refrigerator cylinder increases the COP of the refrigerator by about 40%, especially at low pressures at expansion to compression bore ratio of 2.0. The proposed refrigerator can achieve a cooling capacity of 450 W at COP = 0.9 under a charged pressure of 5 bar. Comparing the current work and earlier studies shows that the proposed refrigerator achieves a 60% improvement in cooling load at the same changing pressure.