Exergy analysis of a refrigeration compressor

• Main Author: Lee, Staniel Keng Yong.
• Other Authors: Ooi Kim Tiow
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Mechanical engineering::Energy conservation
• Online Access: http://hdl.handle.net/10356/39573
• Institution: Nanyang Technological University

An exergy analysis of a refrigeration compressor is presented in this report. The purpose is to identify and investigate the exergy losses on a rotary compressor, namely the rolling piston compressor. The exergy losses are attributed to heat transfers, adiabatic throttling, irreversible fluid mixing and frictions. They are described on a common basis, as exergy destruction rate or irreversibility. To achieve this, a mathematical model of the rolling piston compressor was first formulated. The model accounts for the geometrical configuration, valve flow, thermodynamics effects and mechanical considerations. To facilitate the theoretical analysis on the compressor model, the thermodynamics first and second law were reviewed. Next, the exergy theory was introduced with detailed irreversibility equations formulated for the heat transfers, adiabatic throttling, irreversible fluid mixing and frictions mechanisms. The irreversibility equations were implemented into current compressor simulation program using refrigerant R22. Different variables were used to investigate the exergy destruction rate by the mechanisms mentioned. The results that were presented consist of graphs for the adiabatic throttling, fluid mixing and thermodynamic properties. Tables of the breakdown of different friction mechanisms were also tabulated. The use of irreversibility equations in the simulation had proven to be essential to identify the locations which experienced the most exergy losses. Due to the time constraint, the author was only able to vary a few parameters for the simulation. But it was good enough to understand the exergy transfer for different mechanisms.