Copper Oxide Nanoparticles for Advanced Refrigerant Thermophysical Properties: Mathematical Modeling

In modern days, refrigeration systems are important for industrial and domestic applications. The systems consume more electricity as compared to other appliances. The refrigeration systems have been investigated thoroughly in many ways to reduce the energy consumption. Hence, nanorefrigerant which is one kind of nanofluids has been introduced as a superior properties refrigerant that increased the heat transfer rate in the refrigeration system. Many types of materials could be used as the nanoparticles to be suspended into the conventional refrigerants. In this study, the effect of the suspended copper oxide (CuO) nanoparticles into the 1,1,1,2-tetrafluoroethane, R-134a is investigated by using mathematical modeling. The investigation includes the thermal conductivity, dynamic viscosity, and heat transfer rate of the nanorefrigerant in a tube of evaporator. The results show enhanced thermophysical properties of nanorefrigerant compared to the conventional refrigerant. These advanced thermophysical properties increased the heat transfer rate in the tube. The nanorefrigerant could be a potential working fluid to be used in the refrigeration system to increase the heat transfer characteristics and save the energy usage. 1. Introduction A new emerging heat transfer fluid called nanofluid has been introduced in many applications nowadays such as electronic, nuclear reactor, biomedical, automotive, and industrial cooling. In recent years, refrigerant-based nanofluids and nanorefrigerants have been introduced as significant effects of nanoparticles in heat transfer performance and energy consumption reduction [1–3]. Past researches of nanofluids have shown that low concentration of nanoparticles has a promising potential to enhance the thermophysical properties of the base fluids. Since then, the investigations of nanoparticles suspension in the conventional refrigerant have been conducted tremendously. A study proved that the nanoparticles suspension in domestic refrigerators in Malaysia could reduce the energy consumption about 10,863？MWh by the year 2030 [4]. Many studies have been conducted to investigate the thermal conductivity of the nanofluids. However, there are limited literatures on the nanorefrigerants thermal conductivity [5]. However, researchers agreed that the nanoparticles concentration and types of nanoparticles increased the thermal conductivity of the nanorefrigerant [1, 6]. A long term stability of nanoparticles dispersion affects the thermal conductivity of the nanorefrigerant since better dispersion behavior showed higher thermal