Synthesis of nano silica particle from silica sand and characterization of nano silica based R134a refrigerant

Abstract

This paper presents the synthesis and characterization of a mixture of different percentages of nano-silica with R134a as a refrigerant material. This work shows ways for enhancing the thermal performance of the vapor compression process and the effect of the suspended silica nanoparticle in the R134a refrigerant. Thermal characteristics such as thermal conductivity, specific heat, enthalpy of vaporization, boiling point, freezing temperature, critical temperature, and vapor density were measured. A comparative parametric study was also carried out between traditional R134a and nano-silica mixed R134a. Results show that the addition of 2% of nano-silica particles to R134a refrigerant leads to an increase in thermal conductivity from 0.009 to 0.011 W/m °C at 20 °C. The addition of the same amount of nano-silica to R134a refrigerant, leads to an increase in enthalpy of vaporization from 217 to 220.7 kJ/kg. Moreover, specific heat was decreased from 1.41 to 1.21 kJ/kg k, boiling temperature from −26 °C to −34 °C, and freezing temperature from −103.4 °C to −108.3 °C. These changes in the property of the proposed refrigerant are capable of enhancing the thermal properties in the vapor compression refrigeration cycle. The outcome of this research helps to develop household refrigerators with effective refrigerants that would make them more accessible for low-income and developing countries.