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Theoretical Evaluation of the Vapor Compression Cycle With a Liquid-Line/Suction-Line Heat Exchanger, Economizer, and Ejector (NISTIR 5606)

Published

Author(s)

Piotr A. Domanski

Abstract

The report presents a theoretical analysis of three vapor compression cycles which are derived from the Rankine cycle by incorporating a liquid-line/suction-line heat exchanger, economizer, or ejector. These addendums to the basic cycle reduce throttling losses using different principles, and they require different mechanical hardware of different complexity and cost. The theoretical merits of the three modified cycles were evaluated in relation to the reversed Carnot and Rankine cycle. Thirty-eight fluids were included in the study using the Carnahan-Starling-DeSantis equation of state. In general, the benefit of these addendums increases with the amount of the throttling losses realized by the refrigerant in the Rankine cycle. The liquid-line/suction-line heat exchange cycle shows the smallest COP improvement. Theoretically, the ejector cycle can reach the highest COP, but this requires a high level of ejector efficiency, which has not been demonstrated to be feasible in practice. If the two-phase ejector efficiency is assigned the value attainable in a typical single-phase ejector, the COP of the ejector cycle is comparable to the COP of the one-stage economizer cycle.
Citation
NIST Interagency/Internal Report (NISTIR) - 5606
Report Number
5606

Keywords

air conditioning, ejector, liquid-line/suction-line heat exchange, Rankine cycle, refrigeration, vapor compression cycle

Citation

Domanski, P. (1995), Theoretical Evaluation of the Vapor Compression Cycle With a Liquid-Line/Suction-Line Heat Exchanger, Economizer, and Ejector (NISTIR 5606), NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.IR.5606 (Accessed April 17, 2024)
Created March 1, 1995, Updated June 2, 2021