Experimental Investigation of a Two-Stage Cascade Refrigeration System using different Capillary Combinations

Abstract

A cascade system integrates two vapor compression cycles connected through an intermediate heat exchanger, enabling effective heat transfer between the stages while minimizing exergy losses. This paper presents the experimental analysis of a two-stage cascade refrigeration system using R134a and R32 as refrigerants in the low and high temperature cycles, respectively. The objective is to achieve ultra-low temperature refrigeration with enhanced energy efficiency and reduced environmental impact. In this study, two different capillary tube combinations of different diameters were employed to evaluate and compare the performance of cascade system. The cascade system's performance was tested under varying ambient temperatures. In our present experimental work, performance evaluation of cascade system was carried out by measuring key parameters such as coefficient of performance, refrigeration capacity, compressor input work and heat rejection rate. The results showed that maximum actual refrigeration capacity of 0.991 kW and heat rejection rate of 5.496 kW was achieved at an ambient temperature of 32°C. At this condition, the system also exhibited the lowest compressor work of 1.238 kW with minimum temperature attained as -24°C. The experimental results indicate that the cascade system offers superior thermodynamic efficiency compared to conventional single-stage systems, particularly at lower temperature ranges. R134a/R32 refrigerant combination proved to be a viable and environmentally friendly option, making the system suitable for applications like biomedical storage, cryogenics and low-temperature industrial processes.

Keywords

• Two-stage cascade refrigeration system
• capillary tube combinations
• coefficient of performance
• energy efficiency
• ultra-low temperature
• environmental impact.

References

1. J. J. Fiori, C. U. S. Lima, and V. Silveira Junior, “Theoretic-experimental evaluation of a cascade refrigeration system for low temperature applications using the pair R22/R404A,” Thermal Engineering, vol. 11, no. 1–2, pp. 7–14, 2012.
2. J. A. Solanki, “Thermodynamic Performance Analysis of Cascade Refrigeration System-A Review,” International Journal of Science and Research, vol. 9, no. 7, pp.1024-1098, 2020.
3. Y. Xu, R. Langebach, and U. Hesse, “Design of a cascade refrigeration system for applications below -50°C using CO2-sublimation,” in Proc. 17th Int. Refrig. Air Cond. Conf. at Purdue, West Lafayette, IN, USA, July 9–12, 2018, Art. no. 2168.
4. M. J. S. Jadhav, A. Professor, and M. A. D. Apte, “Review of cascade refrigeration system with different refrigerant pairs,” International Journal of Innovations in Engineering Research and Technology, vol. 2, no. 6, pp. 1–8, 2015.
5. S. Ponsankar, C. Balasuthagar, A. Sathish Kumar, M. Ijas Ahmed, and K. Kaman, “Performance and Irreversibility analysis of two stage cascade refrigeration system for different refrigerant pairs,” Journal of Chemical and Pharmaceutical Sciences, vol. 10, no. 1, pp. 371–375, 2017.
6. B. Yilmaz, N. Erdonmez, M. K. Sevindir, and E. Mancuhan, “Thermodynamic analysis and optimization of cascade condensing temperature of a CO2 (R744)/R404A cascade refrigeration system,” in Proc. 15th Int. Refrig. Air Cond. Conf. at Purdue, West Lafayette, IN, USA, July 14–17, 2014, Paper 1541.
7. U. C. Rajmane, “Cascade Refrigeration System: R404a-R23 Refrigerant,” Asian Journal of Electrical Sciences, vol. 6, no. 1, pp. 18–22, 2017, doi: 10.51983/ajes-2017.6.1.1993.
8. E. Mançuhan, B. Tunç, K. Yetkin, and C. Çelik, “Comparative analysis of cascade refrigeration systems’ performance and environmental impacts,” Journal of Turkish Chemical Society Section B: Chemical Engineering, vol. 2, no. 2, pp. 97–108, 2019.

9. B. Yilmaz, E. Mançuhan, and D. Yilmaz, “Theoretical analysis of a cascade refrigeration system with natural and synthetic working fluid pairs for ultra-low temperature applications,” Journal of Thermal Science and Technology, vol. 40, no. 1 pp. 141–153, 2020.
10. V. Kumar, M. N. Karimi, and S. K. Kamboj, “Comparative analysis of cascade refrigeration system based on energy and exergy using different refrigerant pairs,” Journal of Thermal Engineering, vol. 6, no. 1, pp. 106–116, Jan. 2020.
11. M. T. Scholar, S. Naga, K. Pal, and S. Rajput, “Comparative Thermodynamic Performance Analysis of a Cascade System using Different Refrigerant Couples,” International Journal of Science Engineering and Technology, vol. 8, no. 5, pp. 1-9, 2020.
12. Rangel, V. B., Almeida, A. G. S., Almeida, F. S., & da Cruz Duarte, L. G. “Cascade refrigeration system for low temperatures using natural fluids,” Revista Foco, vol. 15, no. 1, p. 295, Aug. 2022, doi: 10.54751/revistafoco.v15n1-013.
13. Z. Sun et al., “Performance comparison of the single-refrigerant cascade refrigerating system,” Energy Reports, vol. 8, pp. 8259–8270, Nov. 2022, doi: 10.1016/j.egyr.2022.06.055.
14. R. Cabello, A. Andreu-Nácher, D. Sánchez, R. Llopis, and F. Vidan-Falomir, “Energy comparison based on experimental results of a cascade refrigeration system pairing R744 with R134a, R1234ze(E) and the natural refrigerants R290, R1270, R600a,” International Journal of Refrigeration, vol. 148, pp. 131–142, Apr. 2023, doi: 10.1016/j.ijrefrig.2023.01.009.
15. S. Kumar, A. Pandey, A. K. Singh, A. Kumar, and C. K. Yadav, “Comparison of thermodynamic performance in cascade systems utilizing various refrigerant combinations,” Scientx Journal of Mechanical Engineering Technology, vol. 2, no. 1, pp. 1–12, 2024.
16. R. Shi, T. Bai, and J. Wan, “Performance analysis of a dual-ejector enhanced two-stage auto-cascade refrigeration cycle for ultra-low temperature refrigeration,” Applied Thermal Engineering, vol. 240, Mar. 2024, Art. no. 122152, doi: 10.1016/j.applthermaleng.2023.122152.
17. S. J. Kline and F. A. McClintock, “Describing uncertainty in single sample experiments,” Mechanical Engineering, vol. 75, pp. 3–8, 1953.