Journal of Renewable and New Energy

Thermodynamic modeling and performance evaluation of the economizer effect on increasing the efficiency of air-cooled compression chillers

Articles in Press

Document Type : Original Article

Authors

Ahmad Reza Mollakazemi 1
Jamasb Pirkandi 2
Mahdi Hashem Abadi 3
Seyed Mohammad Navid Tabatabaei Zadeh 4

1 M.Sc Student, Faculty of Aerospace, Malek Ashtar University of Technology, Tehran, Iran

2 Associate Professor, Faculty of Aerospace, Malek Ashtar University of Technology, Tehran, Iran.

3 Assistant Professor, Faculty of Aerospace, Malek Ashtar University of Technology, Tehran, Iran.

4 M.Sc Student, Energy Systems Engineering, University of Tehran, Tehran, Iran

Abstract
Since the invention of refrigeration systems, human living standards have increased rapidly. Air conditioners have provided people with comfort regardless of external conditions, and refrigerators have significantly improved the quality of human food. Since refrigeration systems with high energy efficiency require less energy for the same amount of cooling or heating capacity, they reduce electricity demand. Therefore, improving the performance of the refrigeration system can be a valid approach to preserving the environment. In this study, the thermodynamic performance of an air-cooled vapor compression chiller equipped with an economizer was investigated. The main objective was to evaluate the effect of the economizer on the coefficient of performance (COP), compressor power reduction, and overall energy efficiency improvement. Two models—a two-stage vapor compression cycle and a single-stage cycle with an economizer were developed and simulated using EES software. Eight different refrigerants were analyzed. The simulation results showed that employing an economizer enhanced the COP by 10–15% compared with the conventional system. Among the studied refrigerants, R1234ze(Z) exhibited the highest thermal efficiency and environmental compatibility, while R407C demonstrated the lowest performance. Parametric analysis revealed that an increase in condenser temperature leads to a reduction in COP and a higher compressor power requirement.

Keywords

Air-cooled chiller
Economizer
Coefficient of performance
Refrigerant
Thermodynamic analysis
Subjects
Journal of Renewable and New Energy

Articles in Press, Accepted Manuscript
Available Online from 23 July 2026

  • Receive Date 14 December 2025
  • Revise Date 29 April 2026
  • Accept Date 09 June 2026

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