Title: Parametric exergy analysis of a two-stage vapour compression cycle for freeze desalination comparing eco-friendly refrigerants

Authors: Shrikant Jadhav; S. Pavitran; Suresh Gosavi

Addresses: Department of Technology, Savitribai Phule Pune University, Pune 411007, India ' Vishwakarma Institute of Technology, Pune 411037, India ' Department of Physics, Savitribai Phule Pune University, Pune 411007, India

Abstract: The current work aims to analyse a two-stage vapour compression refrigeration (TSVCR) cycle for freeze desalination. In this system, a low-pressure reversible subsystem (LPS) performs simultaneous freezing-thawing. The high-pressure subsystem (HPS) ensures cycle thermal stability. A mathematical model is developed to evaluate energy and exergy performance. Three eco-friendly refrigerants [R1234ze(E), R1234yf and R1243zf] are considered and compared with R22. The results show COP ranging from 6.5 to 12.7, with a specific energy consumption of 8.2 to 14.8 kWh/m³ of freshwater. The highest exergy efficiency of 38.4% is reported for R1243zf, which is higher by 1-3%, compared to R22 and R1234ze(E). However, R1234yf exhibits 11.14% and 7.8% lower energy and exergy performance. The maximum exergy destruction arises from the low pressure compressor (29%) followed by the latent heat condenser (23%). The uncondensed refrigerant significantly affects the performance and thermal stability. The study shows R1243zf and R1234ze are good alternatives to R22 due to their better energy and exergy performance.

Keywords: two-stage vapour compression; freeze desalination; exergy analysis; eco-friendly refrigerants; specific energy consumption.

DOI: 10.1504/IJEX.2022.124740

International Journal of Exergy, 2022 Vol.39 No.1, pp.61 - 80

Received: 07 Mar 2021
Accepted: 25 Nov 2021
Published online: 08 Aug 2022 *

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