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Second law analysis for refrigeration cycles with refrigerant mixtures.

Author(s) : TARNAWSKI V. R., AITTOMÄKI A., POLONARA F.

Summary

Second law analysis was applied to an expanded standard refrigeration cycle with a cooling tower and a cold room. The analysis focused on the following mixtures: R22/R218, R22/R142b/R218, R22/R134a/R218, R134a/R125/R600, R134a/R125/R32, and R125/32. For binary refrigerants, the composition was varied from 0 to 1 while for ternary mixtures a fraction of one refrigerant was assumed to be constant. The R22 influence is a positive one, particularly in a binary mixture with R218, where the cycle net rational efficiency (RE) increases at an average rate of 17%; a big drop in the relative irreversibility rate for the throttler region (rate at 29%) was obtained. The presence of R134a in investigated mixtures is also a beneficial one. The RE increases at an average rate of 7 and 5% respectively with increased fraction of R134a. The increase of the R125 fraction in investigated binary and ternary mixtures leads generally to the decrease in the RE. This outcome is caused mainly by considerable irreversibility gains in the throttler. Generally, a noticeable decrease in irreversibility losses in the throttler region is a key factor leading to the cycle net rational efficiency increase. The paper concludes with a number of postulates regarding the application and future development of the computer package.

Details

  • Original title: Second law analysis for refrigeration cycles with refrigerant mixtures.
  • Record ID : 2003-0062
  • Languages: English
  • Source: Arab-African Conference for Refrigeration and Air Conditioning.
  • Publication date: 2001/04/01
  • Document available for consultation in the library of the IIR headquarters only.

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