Performance of automotive air conditioning system using al2o3-sio2 nanolubricants

Enhancement in the coefficient of performance (COP) of the automotive air conditioning (AAC) system is necessary to reduce fuel consumption. A novel approach for improvement in refrigeration system performance is by dispersing nanoparticles in the conventional lubricant of AAC compressor. However, single-component lubricant applications contribute limitations on stability, compressor work, wear rates and AAC performance. The recent trend in nanoparticle dispersion technology is by utilizing two or more metal or metal oxide nanoparticles in existing lubricant and is known as composite nanolubricants. The composite nanolubricants is expected to improve the properties of single-component nanolubricants in achieving enhancement in thermal properties, rheological properties, stability, and AAC system performance. The aims of the present study are to evaluate the properties of metal oxide composite nanolubricants and to investigate the optimum condition of the AAC system performance using the best combination of composite nanolubricants. Metal oxide nanoparticles were dispersed in the Polyalkylene Glycol (PAG) 46 lubricant with different combinations of two types of nanoparticles using the two-step method of preparation. The composite nanolubricants was prepared up to 0.1% volume concentration with a variation of nanoparticle composition ratios. Thermal physical properties of different metal oxide composite nanolubricants were measured at temperatures of 30 to 80 °C. Then, the thermal physical properties of Al2O3-SiO2/PAG composite nanolubricants were measured with a variation of nanoparticle composition ratios and volume concentrations. Tribological properties of the composite nanolubricants were evaluated for different loads and speeds. The experimental investigation for the AAC performance was carried out using Al2O3-SiO2/PAG composite nanolubricants (best metal oxide combination) by varying the composition ratios and volume concentrations. Compound optimization technique using the Taguchi and Response Surface Methodology (RSM) methods were selected to optimize the AAC system. Stability evaluation showed Al2O3-SiO2/PAG composite nanolubricants having an excellent stability condition with no sedimentation observed within a month. It was proven by the measurement of the zeta potential up to 61.1 mV and maintenance of the concentration ratio of UV-Vis spectrophotometer of more than 90%. Thermal conductivity and dynamic viscosity of the composite nanolubricants increased with volume concentration and decreased with temperature. The tribological properties observation with optimal conditions of coefficient of friction (COF) and wear rates were found at 0.02% volume concentration. The COF and wear rates were reduced to 4.49% and 12.99%, respectively. The composite nanolubricants at 60:40 composition ratio was observed to be the most effective composition ratio and recommended by the properties evaluation of the nanolubricants. The maximum COP enhancement was achieved up to 28.10% with 0.015% volume concentration and 60:40 composition ratio of Al2O3-SiO2/PAG composite nanolubricants. Consequently, the AAC system parameter namely composition ratio, compressor speed, initial refrigerant charge, and volume concentrations of 60:40, 900 rpm, 155 g and 0.019% respectively were optimized using the compound optimization technique. The optimization results yield optimum cooling capacity, compressor work, COP, and power consumption of 0.94 kW, 19.20 kJ/kg, 9.05 and 0.62 kW, respectively, with highest desirability of 81.60%. Finally, it can be concluded that 0.019% is the optimum volume concentration for Al2O3-SiO2/PAG nanolubricant. Therefore, 0.019% Al2O3-SiO2/PAG with composition ratio of 60:40 was highly recommended for the optimum performance in AAC system

Performance of air-conditioning system with different nanoparticle composition ratio of hybrid nanolubricant

To reduce fuel consumption, the automotive air-conditioning (AAC) system’s coefficient of performance (COP) needs to be improved. The use of a diverse selection of hybrid nanolubricant composition ratios is expected to improve the properties of single nanolubricants, resulting in improved AAC system performance. The goal of this study was to find the best combination of hybrid nanolubricants for the best performance of the AAC system. Al2O3-SiO2/PAG hybrid nanolubricants at 0.06% volume concentrations with various composition ratios (20:80, 40:60, 50:50, 60:40, and 80:20) were investigated. An initial refrigerant charge of up to 155 g and a compressor speed of up to 2100 rpm were used in the experiment. The cooling capacity, compressor work, and COP of the AAC system were measured to determine its efficiency. The COP enhancement and compressor work reduction were recorded up to 16.31% and 18.65% for the 60:40 composition ratio, respectively. The maximum cooling capacity up to 75.84% was recorded for the 80:20 ratio, followed by 60:40. The maximum COP value of 8.81 for 155 g of hybrid nanolubricants was obtained at 900 rpm with a 60:40 composition ratio. Therefore, for optimal performance in the AAC system, a 60:40 composition ratio of the Al2O3-SiO2/PAG nanolubricant combination is strongly recommended

Performance optimization of automotive air-conditioning system operating with al2o3-sio2/pag composite nanolubricants using taguchi method

The performance of an automotive air-conditioning (AAC) system is influenced by a variety of operating conditions. This can be addressed by employing optimization techniques that can suggest the appropriate parameters for the best results. In this study, the optimum operating conditions for a composite nanolubricants-fuelled AAC system were investigate using Taguchi's design of experiment approach and analysis of variance (ANOVA). The motor speed value, initial refrigerant charge, and composite nanolubricants composition ratio were chosen as operating parameters to investigate the AAC system performance, focusing on the coefficient of performance (COP) and compressor work. Orthogonal arrays (ORs) L25 (56) was selected to determine the optimum operating parameters of the AAC system. The optimum values for speed, refrigerant mass, and composition ratio were determined to be A4B1C5 (60:40, 900 rpm and 155 g), respectively. The motor speed was the significant factor influencing both COP and compressor performance by 78.13% and 89.29%. A confirmation test was conducted with the optimum levels of AAC system parameters to verify the efficiency of the Taguchi optimization method. The validation between the optimization results and the experimental results yielded a maximum error of 9.85%, indicating that the findings of this investigation were acceptable

Stability and thermal conductivity of mono and hybrid nanoparticles dispersion in double-end capped pag lubricant

Stable nanolubricant mixtures are interrelated with thermal conductivity enhancement, thus improving heat transfer performance in automotive air conditioning (AAC) systems. This paper studies the stability and thermal conductivity of double-end capped polyalkylene glycol (PAG)-based nanolubricants specially designed for R1234yf refrigerant. Mono nanolubricants (Al2O3/PAG and SiO2/PAG) and hybrid nanolubricants (Al2O3–SiO2/PAG) were prepared using a two-step preparation method at different volume concentrations of 0.01 to 0.05%. The stability of these nanolubricants was observed by visual, UV-Vis spectrophotometer, and zeta potential. Thermal conductivity (k) was measured from 30 to 70 °C using a C-Therm thermal properties analyser. The results from the stability analysis show that all nanolubricants were confirmed in excellent stability conditions for more than six months with minimum visual sedimentation, more than 70% concentration ratio, and zeta potentials greater than 60 mV. The Al2O3–SiO2/PAG samples recorded the highest values of thermal conductivity increment, followed by the Al2O3/PAG and SiO2/PAG samples with 2.0%, 1.7%, and 1.5% enhancement. Hybrid nanolubricants have been shown to have greater potential in the AAC system because of their excellent stability and better property enhancement in thermal conductivity

Viscosity and friction reduction of double end capped polyalkylene glycol nanolubricants for eco friendly refrigerant

In sustainable tribology, researchers are investigating methods to enhance tribological performance by incorporating nanoparticles into lubricants. However, one potential drawback of this strategy is increased lubricant viscosity. The current study aimed to assess the impact of these nanoparticles on the viscosity and coefficient of friction (COF) of the nanolubricants. Three different nanolubricants were synthesized through a two-step process, including mono-nanolubricants (Al2O3/DEC PAG and SiO2/DEC PAG) and hybrid nanolubricants (Al2O3-SiO2/DEC PAG), at volume concentrations between 0.01% and 0.05%. The viscosity and shear flow behavior of these nanolubricants were evaluated using a digital rheometer, while the COF was measured using a Koehler four-ball tribometer. All the nanolubricants showed Newtonian behavior during the experiments. The dynamic viscosity velocity increment of SiO2/DEC PAG was found to be the lowest (1.88%), followed by Al2O3-SiO2/DEC PAG (2.74%) and Al2O3/DEC PAG (3.56%). The viscosity indices of all the nanolubricants were improved only at higher concentrations. At a volume concentration of 0.03%, the Al2O3-SiO2/DEC PAG nanolubricant reduced the COF by up to 8.1%. The results showed that the combination of nanoparticles, temperature, and volume concentration significantly influenced the viscosity and COF of nanolubricants. This study provides essential information for developing high-performance nanolubricants with improved viscosity and COF and advancing environmentally friendly tribology solutions

Tribology Performance of TiO2-SiO2/PVE Nanolubricant at Various Binary Ratios for the Automotive Air-conditioning System

Tribological properties are crucial for air-conditioning system performance. The properties can be improved using nanolubricant. However, the effect of the binary ratio of hybrid nanolubricants on the tribological performance of automotive systems is limited in the literature. Therefore, the present study investigates the tribology performance of TiO2-SiO2 nanolubricants for application in automotive air-conditioning (AAC) systems. The dispersion of TiO2 and SiO2 into PVE lubricant was carried out using a two-step method. Subsequently, the dispersion stability was assessed qualitatively and quantitatively. The samples were characterised by a volume concentration of 0.010%, with variations in the mixture ratio of 20:80, 40:60, 50:50, 60:40, and 80:20. Coefficient of friction (COF) and wear scar diameter (WSD) values were determined using the Koehler Four-ball Tribo Tester and Light Compound Microscopy. The investigation revealed that each sample experienced a reduction in COF, with the 40:60 ratio demonstrating the best ratio with the most significant decrease of 37.09%. At the same time, the COF decreased by 8.34%, 2.12%, 7.37%, and 15.11% for the nanolubricant samples at 20:80, 50:50, 60:40, and 80:20, respectively. The WSD evaluation showed that the 40:60 ratio has the lowest scar diameter of 0.0344 mm and a 37.09% wear rate decrease compared to pure lubricant. Each sample exhibits superior performance when evaluated for tribological characteristics and performance, particularly in the case of nanolubricants with the 40:60 ratio. The TiO2-SiO2/PVE, characterised by a volume concentration of 0.010%, has remarkable efficacy across different binary ratios, making it highly recommended with a 40:60 ratio for lubricating AAC compressor systems

Stability assessment of polyvinyl-ether-based TiO2, SiO2 and their hybrid nanolubricants

Poor characterisation of nanoparticle suspensions impedes the development of nanolubricants for use in refrigeration and air-conditioning systems. Chemical treatment techniques, such as surfactants, are inappropriate for enhancing the stability of nanolubricants intended for use in vapour-compression refrigeration (VCR) systems. Prior to incorporating nanolubricants into the system, the stability of TiO2 and SiO2 nanoparticles dispersed in PVE was therefore investigated. The nanolubricants were prepared by a two-step method with the aid of an ultrasonication bath homogeniser. Visual observation and ultraviolet–visible (UV–Vis) spectrophotometric analysis were used, and zeta potential analysis was then performed to confirm the nanolubricants’ stability condition. The TiO2/PVE nanolubricant was observed to be maintained at a 95% concentration ratio for up to 30 days of evaluation. The TiO2/PVE, SiO2/PVE, and SiO2-TiO2/PVE exhibited zeta potential values of 203.1 mV, 224.2 mV, and 105.3 mV, respectively, after 7 h of sonication. A high absolute value of zeta potential indicates that the electrostatic repulsive forces between nanoparticles are exceptionally strong, indicating an excellent stable suspension. The high values of zeta potentials validated the excellent stability conditions determined by UV–Vis analysis and visual observation. It can be concluded that ultrasonication times of 7 h produced the most stable state for mono- and hybrid nanolubricants

Performance of Al2O3/TiO2 hybrid nano-cutting fluid in mql turning operation via RSM approach

Cutting fluids can be used to cool workpieces at high cutting speeds and remove chips from cutting zones. The effectiveness of cutting fluids may be improved with the addition of hybrid nanoparticle dispersion. This study evaluates the effectiveness of an Al2O3-TiO2 hybrid as a cutting fluid in turning operations. The Al2O3-TiO2 hybrid nano-cutting fluid was prepared using a one-step method in computer numerical control (CNC) coolant with concentrations of up to 4%. Utilizing air-assisted nano-cutting fluids injected through a minimum quantity lubrication (MQL) setup, the effectiveness of turning cutting performance, cutting temperature (°C), average surface roughness (Ra), and tool wear (%) were evaluated. Then, the response surface method (RSM) was utilized as the design of experiment (DOE) to optimize the turning cutting performance parameters. The combination of 4% hybrid nano-cutting fluid concentration, 0.1 mm/rev feed rate, and 0.55 mm depth of cut yielded the lowest cutting temperature, surface roughness, and tool wear values of 25.3 °C, 0.480 µm, and 0.0104%, respectively. The 4% concentration of Al2O3/TiO2 hybrid nano-cutting fluid inclusion achieved the highest surface roughness reduction that led to better surface finish and the lowest tool-wear reduction led to longer tool life. Therefore, Al2O3/TiO2 hybrid nano-cutting fluids were strongly recommended in turning operations for CNC lathes

Comprehensive review of nanoparticles dispersion technology for automotive surfaces

Many innovations arose from the continual and thorough monitoring of overlooked characteristics of materials found in the environment. Automotive paints are always constantly exposed to a broad range of ambient temperature conditions, which reduces their longevity and encourages algae development. Through the effective incorporation of nanotechnology with this lotus effect, it has become possible to provide self-cleaning ability along with air purification and antibacterial performance to automotive surfaces like paint and coating. The addition of nanoparticles such as Titanium dioxide (TiO2) and Silicon dioxide (SiO2) helps to improve functionalities like water or stain resistance, ultra-violet protection, and scratch resistance. When the nanoparticles were added into paint, they degraded the polluting compounds on the material's surface by photo catalysis. Multiple photocatalytic functions and self-cleaning properties were observed in nanoparticles added to polyester acrylic paint. Therefore, this paper discussed the history of automotive painting, nanopaint technology, previous research on the method preparation, development, and current progress, the environmental health aspects of nanotechnology, as well as the performance in terms of automotive surfaces. The study discovered the requirements for nanoparticle dispersion and coating uniformity and appearance on automotive surfaces, which will serve as a benchmark for dispersion and coating methods for automotive surfaces

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