Investigation of Thermal Conductivity and Viscosity of Al2O3/PAG Nanolubricant for Application in Automotive Air Conditioning System

In this paper, thermal conductivity and viscosity of the Al2O3/polyalkylene glycol (PAG) 46 nanolubricants for 0.05 to 1.0% volume concentrations at temperatures of 303.15 to 353.15 K have been investigated. Al2O3 nanoparticles were dispersed in the PAG lubricant by a two step preparation. The measurement of thermal conductivity and viscosity was performed using KD2 Pro Thermal Properties Analyzer and LVDV-III Rheometer, respectively. The results showed that the thermal conductivity of the nanolubricants increased by concentration, but decreased by temperature. Besides, the viscosity of the nanolubricants sharply increased for concentrations higher than 0.3%. However, this parameter diminished by temperature. The highest thermal conductivity and viscosity ratio were observed to be 1.04 and 7.58 times greater than the PAG lubricant for 1.0% and 0.4% concentrations, respectively. As a conclusion, it was recommended to use the Al2O3/PAG nanolubricants with concentration of less than 0.3% for application in automotive air conditioning system

Performance improvement in mobile air conditioning system using Al2O3/PAG nanolubricant

This paper presents the investigation of Al2O3/PAG nanolubricant performance for a compact vehicle mobile air conditioning (MAC) system. The Al2O3/PAG nanolubricant in this study is prepared by using two-step preparation method and stabilized using 4-Step UV–Vis Spectral Absorbency Analysis. An enhancement in the coefficient of performance (COP), reduction in compressor work, and enhancement in the cooling capacity of MAC employing Al2O3/PAG nanolubricant are recorded up to 31%, 26% and 32%, respectively, for 0.010% volume concentration. The current MAC performance is compared with MAC employing SiO2/PAG nanolubricant from previous study. The comparison shows that the Al2O3/PAG nanolubricant has better performance in term of cooling capacity, compressor work, and COP at an average of 6%, 8%, and 33%, respectively. Therefore, the finding from this study suggests Al2O3/PAG nanolubricant with a volume concentration of 0.010% as an optimum and best performance nanolubricant for MAC systems

Sonication Time Effect towards Stability of Al2O3/PAG and SiO2/PAG Nanolubricants

Ultrasonication is the act of applying sound force to agitate particles in a sample with the frequency of more than 20 kHz. It is an external vibration induced during preparation of nanolubricant that helps the particles to overcome the van der Waals force bonding. Nanolubricant prepared is intended to be used in automotive air conditioning (AAC) system to improve its performance. In this work, stability Polyalkylene glycol (PAG) and SiOi/PAG nanolubricants of 0.2 % volume concentrations with different sonication lime were investigated. Five samples for each nanolubricant were prepared by two-step method process with variation of sonication time from zero to two hours' time with half an hour interval. The stability tests were done by visual sedimentation and UV-vis spectrometer. The optimum sonication time found to be one and half hours and two hours for AI2O3/PAG and SiOi/PAG nanolubricants respectively. Both nanolubricants were found stable for more than two weeks 'period

Preparation and Stability of Silicone Dioxide Dispersed in Polyalkylene Glycol based Nanolubricants

Nanolubricant is one of the efforts introduced by researchers to increase efficiency in many mechanical application, especially in refrigeration. Two-step method is the most common method used in the process of adding nanoparticles dispersed in base lubricant because of the simplicity of the process to prepare a stable solution. In this work, the SiO2/PAG nanolubricants were prepared using two-steps method without the use of surfactant. The stability of SiO2/PAG nanolubricant was observed trough sedimentation photograph capturing technique and UVVis spectrophotometric test. The results shown that there are minimum sedimentation observed over one month. This result also confirmed via the UV-Vis test; the nanolubricant relative concentration was maintained at over 70 % compared to the initial concentration

Development of Nanorefrigerants for Various Types of Refrigerant based: A Comprehensive Review on Performance

Nanorefrigerants and nanolubricants are formed when nanoparticles are dispersed in refrigerant/lubricant based. The use of nanorefrigerants or refrigerant with nanolubricant mixtures is one of the passive techniques in enhanced heat transfer performance and reducing energy consumption. This paper reviews the augmentation of heat transfer, enhancement of coefficients of performance (COP) and energy efficiency of various nanoparticle dispersions in the refrigerants or lubricants based on refrigerant type. From the results available in the literatures, it shows that nanorefrigerants and refrigerant/nanolubricant mixtures enhances the heat transfer coefficient. Furthermore, the augmentation of heat transfer coefficient depends on the concentrations and size of the particles. Increment of concentration also increases the viscosity, and consequently, the pressure drop. Moreover, from the review, most of the researchers tend to use R134a hydrofluorocarbon (HFC) as the refrigerant base. Even though the use of chlorofluorocarbon (CFC) refrigerant had been banned, it is still favored by some researchers as it is easy to prepare the nanorefrigerant mixtures in a liquid state with atmosphere pressure and room temperature. The limited research of nanorefrigerants in using hydrocarbon (HC) refrigerant base is due to its flammability issues. Nevertheless, it is strongly suggested that the research based on this environmental friendly refrigerant such as HC need to be conducted extensively

Thermo-Physical Properties of Metal Oxides Composite Nanolubricants

Thermal conductivity and viscosity of the different combination of composite nanolubricants for 0.02% volume concentrations at a temperature range of 30 to 80 "C were investigated. AI2O3, SiO2 and TiO2 nanoparticks were dispersed in the Polyalkylene Glycol (PAG 46) lubricant using the two-step method of preparation. Thermal conductivity and viscosity were measured using KD2 Pro Thermal Properties Analyzer and LVDV-lII Rheometer, respectively. The result shows that the thermal conductivity and viscosity of composite nanolubricants decrease with temperature. Composite nanolubricants behaved as Newtonian in the range of the temperatures studied. The most optimum combination of composite nanolubricant is AljOi-SiOjlPAG as it yields higher enhancement in thermal conductivity but lower in viscosity

Coefficient of Friction and Wear Rate Effects of Different Composite Nanolubricant Concentrations on Aluminium 2024 Plate

Wear of sliding parts and operational machine consistency enhancement can be avoided with good lubrication. Lubrication reduce wear between two contacting and sliding surfaces and decrease the frictional power losses in compressor. The coefficient of friction and wear rate effects study were carried out to measure the friction and anti-wear abilities of Al2O3-SiO2 composite nanolubricants a new type of compressor lubricant to enhanced the compressor performances. The tribology test rig employing reciprocating test conditions to replicate a piston ring contact in the compressor was used to measure the coefficient of friction and wear rate. Coefficient of friction and wear rate effects of different Al2O3-SiO2/PAG composite nanolubricants of Aluminium 2024 plate for 10-kg load at different speed were investigated. Al2O3 and SiO2 nanoparticles were dispersed in the Polyalkylene Glycol (PAG 46) lubricant using two-steps method of preparation. The result shows that the coefficient friction and wear rate of composite nanolubricants decreased compared to pure lubricant. The maximum reduction achievement for friction of coefficient and wear rate by Al2O3-SiO2 composite nanolubricants by 4.78% and 12.96% with 0.06% volume concentration. Therefore, 0.06% volume concentration is selected as the most enhanced composite nanolubricants with effective coefficient of friction and wear rate reduction compared to other volume concentrations. Thus, it is recommended to be used as the compressor lubrication to enhanced compressor performances