Effect of refrigerant charge variation on the energy and thermal performance of a domestic refrigerator

Abstract

Inadequate refrigerant charges can affect the vapor compression refrigeration systems’ thermal and energy performance. To delve deeper into the subject, this study experimentally evaluated the performance of a domestic refrigerator operating at different refrigerant charges. Some of them simulate refrigerant leaks (70 and 80 g), and some others simulate an excess (100 and 110 g). Through a statistical analysis (Tukey test and control graphs), the temperature data with the greatest impact were analyzed, including the temperatures in the suction and in the compressor casing, the temperatures in the middle position and outlet of the condenser and evaporator, as well as the temperatures in the freezer. The operation of the refrigerator was affected to a greater extent when it worked with an overcharge of 110 g; here, the discharge pressure and the run time increased by 1.3 bar and 21%, respectively, compared to the conditions of the refrigerator operating with the reference charge (86 g). In addition, the excess charge also caused an increase in energy consumption of 0.56 kWh/day and a decrease in EER of 0.5 regarding the reference charge. Finally, the increase in energy consumption was projected to $0.03 USD per day with respect to the reference cost.

Keywords

• Domestic Refrigerator
• EER
• Energy
• Refrigerant Charge
• Temperature

References

1. [1] CFE. En esta temporada de calor, la CFE invita a realizar un uso eficiente y responsable de la energía eléctrica. Available at: https://www.cfe.mx/cdn/2019/Archivos/Boletines/125ahorrosvf.pdf. Accessed Oct 8, 2024.
2. [2] ENIGH. Encuesta Nacional de Ingresos y Gastos de los Hogares (ENIGH). 2020 Nueva serie. Available at: https://www.inegi.org.mx/programas/enigh/nc/2020/#Tabulados. Accessed Aug 9, 2021.
3. [3] Choi JM, Kim YC. The effects of improper refrigerant charge on the performance of a heat pump with an electronic expansion valve and capillary tube. Energy 2002;27:391–404. [CrossRef]
4. [4] Hu Y, Yuill DP. Impacts of common faults on an air conditioner with a microtube condenser and analysis of fault characteristic features. Energy Build 2022;254:111630. [CrossRef]
5. [5] Navarro-Esbrí J, Torrella E, Cabello R. A vapour compression chiller fault detection technique based on adaptative algorithms. Application to on-line refrigerant leakage detection. Int J Refrig 2006;29:716–723. [CrossRef]
6. [6] Mehrabi M, Yuill D. Generalized effects of refrigerant charge on normalized performance variables of air conditioners and heat pumps. Int J Refrig 2017;76:367–384. [CrossRef]
7. [7] Chen G, Fang J, Li Z, Zhang S. Theoretical analysis of the impacts of refrigerant leakage on the performance of a flash tank vapor injection heat pump. Int J Refrig 2022;147:10–19. [CrossRef]
8. [8] Li Y, Yang J, Wu X, Liu Y, Zhuang Y, Zhou P, et al. Leakage , diffusion and distribution characteristics of refrigerant in a limited space: A comprehensive review. Therm Sci Engineer Prog 2023;40:101731. [CrossRef]

9. [9] Francis C, Maidment CG, Davies G. An investigation of refrigerant leakage in commercial refrigeration. Int J Refrig 2016;74:10–19. [CrossRef]
10. [10] Bellanco I, Belío F, Vallés M, Gerber R, Salom J. Common fault effects on a natural refrigerant, variable-speed heat pump. Int J Refrig 2022;133:259–266. [CrossRef]
11. [11] Du Z, Domanski AP, Payne WV. Effect of common faults on the performance of different types of vapor compression systems. Appl Therm Engineer 2016;98:61–72. [CrossRef]
12. [12] Grace IN, Datta D, Tassou SA. Sensitivity of refrigeration system performance to charge levels and parameters for on-line leak detection. Appl Therm Engineer 2005;25:557–566. [CrossRef]
13. [13] Deymi-Dashtebayaz M, Farahnak M, Moraffa M, Ghalami A, Mohammadi N. Experimental evaluation of refrigerant mass charge and ambient air temperature effects on performance of air-conditioning systems. Heat Mass Transf Stoffuebertragung 2018;54:803–812. [CrossRef]
14. [14] Kim M, Kim MS. Performance investigation of a variable speed vapor compression system for fault detection and diagnosis. Int J Refrig 2005;28:481–488. [CrossRef]
15. [15] Lee C, Chang YS. Refrigerant charge prediction based on start-up characteristics of an air conditioner using a gray box model. J Mech Sci Technol 2022;36:4859–4868. [CrossRef]
16. [16] Tassou SA, Grace IN. Fault diagnosis and refrigerant leak detection in vapour compression refrigeration systems. Int J Refrig 2005;28:680–688. [CrossRef]
17. [17] Yang J, Wu J, Yu X, Liang Y. Study on fault identification rules for real refrigerant leakage in R290 room air conditioner based random forest algorithm. Expert Syst Appl 2024;238:122126. [CrossRef]
18. [18] Boeng J, Melo C. Mapping the energy consumption of household refrigerators by varying the refrigerant charge and the expansion restriction. Int J Refrig 2014;41:37–44. [CrossRef]
19. [19] Gugulothu SK. Enhancement of household refrigerator energy efficiency by studying the effect of refrigerant charge and capillary tube length. J Therm Engineer 2021;7:1121–1129. [CrossRef]
20. [20] Belman-Flores JM, Heredia-Aricapa Y, García-Pabón JJ, Pérez-García V, Pérez-Reguera CG. Drop-in replacement of R134a in a household refrigerator with low-GWP refrigerants R513A, R516A, and R1234ze(E). Energies 2023;16:3422. [CrossRef]
21. [21] Díaz Cadavid A. Diseño Estadístico de Experimentos. 2nd ed. Colombia: Antioquia University; 2009. [Spanish]
22. [22] Watty AMD. Estadística Para Veterinarios Y Zootecnistas. Mexico City: Newton Edición y Tecnología Educativa; 2016. [Spanish]
23. [23] Li K, Lan J, Zhou G, Tang Q, Cheng Q, Fang Y, et al. Investigation on the influence of refrigerant charge amount on the cooling performance of air conditioning heat pump system for electric vehicles. J Therm Sci 2018;28:294–305. [CrossRef]
24. [24] Pardo-Cely D, Belman-Flores JM, Heredia-Aricapa Y, Rodríguez-Valderrama DA, Morales-Fuentes A, Gallegos-Muñoz A. Fault analysis in a domestic refrigerator: Fan fault, condenser fouling, and area restriction. Int J Refrig 2022;154:290–299. [CrossRef]
25. [25] Mohanraj M, Jayaraj S, Muraleedharan C, Chandrasekar P. Experimental investigation of R290/R600a mixture as an alternative to R134a in a domestic refrigerator. Int J Therm Sci 2009;48:1036–1042. [CrossRef]
26. [26] USDA. Cocinando para Grupos: Guía de Inocuidad Alimentaria para Voluntarios. Available at: https://www.fsis.usda.gov/sites/default/files/media_file/2021-02/Cooking_for_Groups_SP.pdf. Accessed Oct 8, 2024.