Quantifying Inefficiencies in Variable-Speed Reciprocating Compressors: An Exergy Approach

DOI: 10.18462/iir.compr.2024.0634

Sekcia: Reciprocating compressors I

Stav prijatia: Nebol spracovaný

Autori

Abstrakt

This study presents an exergy-based methodology for quantifying losses in small variable-speed reciprocating compressors used in household refrigeration. The methodology integrates compression cycle and thermal models, also accounting for bearings and the electric motor. Validated against experimental data, this approach assesses compressor inefficiencies in terms of irreversibilities from various sources. The analysis covers rotational speeds from 1800 to 6300 rpm under Low Back Pressure (LBP) conditions and reveals that entropy generation increases with compressor speed, predominantly due to losses in valves and mufflers. At low speeds, inefficiencies are primarily driven by leakage in the piston-cylinder clearance and heat transfer between compressor components. A comparative analysis using both the exergy-based method and the traditional p-V diagram at a rotational speed of 3600 rpm shows that the exergy approach highlights inefficiencies in the suction process and heat transfer, whereas the p-V diagram emphasizes losses in the electric motor and bearings.

Kľúčové slová

Reciprocating compressor
Exergy-based analysis
Numerical simulation