International Journal of Vol.5 (No.2). 2023. pp. 63-68 Innovation in Mechanical Engineering & Advanced Materials (IJIMEAM) Published online: December 27, 2023 https://publikasi.mercubuana.ac.id/index.php/ijimeam ISSN: 2477-541X 63 Copyright © 2023. Owned by Author(s). This is an open-access article under CC BY-SA License. EFFECT OF SiO2 AND ZnO NANOPARTICLES TO INCREASE REFRIGERATION MACHINE PERFORMANCE D. Irwansyah 1 , R. Sundari 1* , R. Anggraini 1 , and K. Arifin 2 1 Department of Mechanical Engineering, Universitas Mercu Buana, Kembangan, Jakarta 11650, INDONESIA 2 Fuel Cell Institute, Universiti Kebangsaan Malaysia, Bangi, Selangor 43600, MALAYSIA Abstract In this investigation, the impact of silicon dioxide (SiO2) and zinc oxide (ZnO) nanoparticles on the performance of a refrigeration machine system was systematically examined. The focus was on evaluating the coefficient of performance (COP) concerning the utilization of a polyolester (POE) lubricant, R600a refrigerant, and distinct nanoparticles (SiO2 and ZnO) within the refrigeration system. The nanoparticles were individually introduced into the R600a refrigerant in masses of 0.5 g, 1.0 g, and 1.5 g. The experimental outcomes demonstrated a noteworthy enhancement in COP with the addition of nanoparticles. Specifically, the introduction of 1.5 g of SiO2 resulted in a substantial increase of 25.88% in COP, marking it as the most influential dosage. Similarly, the addition of 1.0 g of ZnO led to a significant COP increase of 13.6%, representing the optimal quantity for ZnO. Furthermore, the inclusion of 1.5 g of SiO2 brought about a remarkable reduction in energy consumption, with a decrease of 25.58%, while 1.5 g of ZnO resulted in a notable 16.28% decrease in energy consumption. The experimental configuration involved the use of 20 g of refrigerant and 500 ml of POE lubricant. Comparative analysis demonstrated that the refrigeration system incorporating nanoparticles outperformed the conventional R600a refrigeration system devoid of nanoparticles. This study contributes valuable insights into the potential enhancements in refrigeration system efficiency through the strategic incorporation of SiO2 and ZnO nanoparticles, offering a promising avenue for optimizing the performance of refrigeration technology. Keywords: Nanoparticle, Nanofluid, Refrigerant, Refrigeration Engine Performance *Corresponding author: Tel. +62 21 5840815 Ext. 5200 E-mail address: rita.sundari@mercubuana.ac.id DOI: 10.22441/ijimeam.v5i2.21859 1. Introduction Nanotechnology is a branch of science and technology strongly related to the rearrangement of particle sizes. In general, particle sizes can be distinguished by their diameter, i.e., coarse particles (10000–2500 nm), fine particles (2500–100 nm), and ultra-fine particles or nanoparticles (1–100 nm) [1]. A nano refrigerant is a type of nanofluid where the primary fluid is a conventional pure refrigerant. Experimental studies reported that nano refrigerants have higher thermal conductivity than conventional refrigerants. In addition, refrigeration systems using nano refrigerants have better performance than conventional pure refrigerants [2]. There are three main reasons that nanoparticles are used as part of refrigerant, i.e. (i) nanoparticles can increase the solubility between lubricant and refrigerant, (ii) nanoparticles increase thermal conductivity and heat transfer of the refrigerant, and (iii) nanoparticles disperse in the lubricant reducing the coefficient of friction and wear rate [3]. Senthilkumar et al. [4] conducted research on refrigerant R600a, mineral oil, and hybrid nanoparticles (SiO2+ZnO) added to a refrigeration machine with a volume fraction of 0.4 g/L and 0.6 g/L and a refrigerant mass of 40 g and 60 g. The results for a mass of 40 g refrigerant with a volume fraction of 0.2 g/L and 0.4 g/L obtained an increase in COP of 30% and 45%, respectively, and for a mass of 60 g refrigerant with a volume fraction of 0.2 g/L and 0.4 g/L obtained an increase in COP of 8% and 31%, respectively. Senthilkumar et al. [5] reported research on R600a refrigerant, POE lubricant, and SiO2 nanoparticles added to a refrigeration machine with volume fractions of 0.2 g/L, and 0.4 g/L and refrigerant mass fractions of 30 g, 40 g, and 60 g. For a volume fraction of 0.2 g/L and 0.4 g/L, the results of 30 g refrigerant found an increase of COP as 56% and 33%, respectively; results of 40 g refrigerant yielded COP increase of 11% and 50%,