Preparation and Performance Analysis of Graphite Nanoparticle in Domestic Refrigerator (original) (raw)
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Procedia Manufacturing, 2019
In this work, the performance of a slightly modified domestic refrigerator infused with various concentrations (0, 0.2, 0.4 and 0.6 g/L) of graphene based nanolubricants and selected mass charges (40, 50, 60 and 70g) of R600a refrigerant was studied. The steady state energetic performance of the domestic refrigerator was evaluated with test parameters including cabinet temperature, compressor power consumption, power per ton of refrigeration (PPTR) and coefficient of performance (COP). Findings showed that the lowest compressor power consumption and cabinet temperature observed within the system were 65 W and-12 o C when infused with either 40g and 0 g/L or 60g and 0.2 g/L nanofluid mixtures. In addition, the utilization of 60 g and 0.2 g/L mixtures gave the highest PPTR value of 5.22 while the maximum COP value of 0.76 was seen with 70 g and 0 g/L respectively. In conclusion, the application of graphene based nanolubricants within the system significantly improved the performance.
Enhancing the thermophysical properties of PAG lubricant using graphene nano-sheets
Journal of Physics: Conference Series, 2019
One of the most attractive methods to improve the thermo physical and heat transfer properties of conventional coolants and lubricants is the use of nanoparticles in it. Nanofluids are stable colloidal suspensions of nanoparticles and base fluids. The nanofluids exhibit superior thermal performance compared to conventional heat transfer fluids and this leads to the best hope for lubricants based nanofluids as well. Nanolubricant is a new class of lubricant produced by dispersing nano-sized particles of metals, metal oxides, carbon and its allotropes into conventional lubricating oils. In the present study, experiments were conducted to measure the thermophysical and rheological properties of polyalkyleneglycol (PAG) refrigerant compressor oil suspended with graphene nano-sheets. The effect of particle concentration and temperature on thermal conductivity and viscosity of nanolubricant were elucidated. The volume fraction is varied from 0.05 to 0.8% and the temperature range is from 15 0 C to 85 0 C. The rheological properties have been investigated at various shear rates, particle concentrations, and temperatures. Furthermore, a correlation is proposed to predict the thermal conductivity of Graphene-PAG nanolubricant. The results revealed that the thermal conductivity and viscosity of the nanolubricant is strongly depends on the volume fraction and temperature. The nanolubricant exhibits higher thermal conductivity and viscosity compared to the PAG oil. Unlike in the case of pure lubricant, the shear rate has a crucial impact on the behavior of nanolubricant. Interestingly, the pure lubricant, which is a Newtonian fluid, is transformed into non-Newtonian when nanoparticles are appended with it. From the studies,, it was observed that the nanolubricant having graphene particle concentration of 0.05% is optimum for refrigeration application.
In this study, usage of nanolubricants containing Al2O3, graphene, and CNTs nanoparticles at various mass fractions in a refrigeration compressor was experimentally investigated. Thus, the required compressor electrical power was measured to determine effects of usage of nanolubricants. Nanoparticles, which were used preparation of nanolubricant were gradually added to the lubricant to determine optimum nanoparticle mass fraction for each nanoparticle kind. Consequently, it was observed that the compressor worked safely and efficiently with nanolubricants. Additionally, optimum mass fractions were determined as 0.750% for Al2O3, 0.250% for graphene, and 0.250% for CNTs for operating conditions of this study. As a result, the required compressor electrical power decreased by 6.26, 6.82, and 5.55% with the addition of Al2O3, graphene, and CNTs nanoparticles at optimum mass fractions of 0.750, 0.250, and 0.250% to the lubricant compared to the compressor using pure oil, respectively. F...
Energy Reports, 2020
The use of graphene nanolubricant to enhance the performance of eco-friendly refrigerant (R600a) in a vapour compression system was investigated. The graphene nanoparticles were dispersed in the base lubricant and prepared for three different samples of graphene nanolubricant concentration of 0.2, 0.4 and 0.6 g/L, the nanolubricant concentrations were investigated in 50, 60 and 70g of R600a refrigerant each. The performances were compared with the base lubricant (mineral oil). The result showed that R600a performed better in graphene nanolubricant compared to the base lubricant in terms of pull-down time, COP, power consumption, cooling capacity. Therefore, graphene nanolubricant can be used as a drop-in replacement for pure mineral oil in the vapour compression system. c
Experimental Study of Performance of R600a/CNT-Lubricant in Domestic Refrigerator System
Lecture Notes in Mechanical Engineering, 2020
Energy consumption and environmental problems have been the major consideration for comfort systems manufacturers. This research work investigated a varied mass charge of R600a, an eco-friendly refrigerant with a low concentration of 0.4 and 0.6 g/L of CNT nanolubricant concentration in a domestic vapor compression refrigerating system working with pure mineral oil as the base lubricant. The experimental test performance of the system was studied considering pull-down time, COP, power consumption, and cooling capacity. The result showed that CNT nanolubricant had lower evaporator air temperature with higher COP and cooling capacity with a reduction in power consumption compared to R600a in the base lubricant in the system.
Evaluation of a Refrigeration System Based on Nano-Refrigerants and Nano-Lubricants
American Journal of Engineering and Applied Sciences, 2021
Most of studies reported that disperse nanoparticles into refrigerants and lubricating oils lead to improve a coefficient of performance, due to improvement of thermal physics properties of a pure fluid, which leads to reduced energy consumption. Using nanoparticles in a refrigeration system is associated with many difficulties such as the cost of preparing and obtaining a stable and homogeneous mixture for a longer time with less agglomeration and sedimentation. In this research, nanoparticles were prepared as a mixture in an inexpensive and easy way consisting of copper and cerium oxides for the first time, with suitable average diameter to verify the possibility of overcoming the problem of stability of nanoparticles for a longer time with refrigerant. As most studies focus on improving the thermal properties of a refrigerant by using high thermal conductivity nanoparticles, while this study focuses on improving both of thermal conductivity of refrigerant and stability of nanoparticles with a refrigerant. Some studies have reported on the use of copper oxide and its effect on improving the performance of refrigeration system, but cerium oxide has not been used in refrigeration systems and this research will open the door to cerium oxide as a single material and as a mixture with copper oxide to verify the possibility of this oxide to create greater stability of nanoparticles and improve thermal properties.
Experimental Study of Thermal Properties and Dynamic Viscosity of Graphene Oxide/Oil Nano-Lubricant
Energies
This experimental study was carried out based on the nanotechnology approach to enhance the efficacy of engine oil. Atomic and surface structures of graphene oxide (GO) nanoparticles were investigated by using a field emission scanning electron microscope and X-ray diffraction. The nano lubricant was produced by using a two-step method. The stability of nano lubricant was analyzed through dynamic light scattering. Various properties such as thermal conductivity, dynamic viscosity, flash point, cloud point and freezing point were investigated and the results were compared with the base oil (Oil- SAE-50). The results show that the thermal conductivity of nano lubricant was improved compared to the base fluid. This increase was correlated with progressing temperature. The dynamic viscosity was increased by variations in the volume fraction and reached its highest value of 36% compared to the base oil. The cloud point and freezing point are critical factors for oils, especially in cold ...
Graphene Nanofluids as a Promising Lubricant and its Sustainability
RESEARCH REVIEW International Journal of Multidisciplinary, 2020
The engineered nanofluids are the best nanoparticles colloidal suspensions in base fluids which had made attention for the young researchers for the performance enhancement focusing on heat transfer properties. In present scenario, the coolants exhibit the outstanding thermal conductivity with application of nanoparticles. Several attempts had made for this application. When compared to various types of nanofluids graphene nanofluids made a great attention from the world of fluid sciences because of its excellent physical, thermal and mechanical properties. Most of the researchers had developed, prepared, synthesized and, characterised the graphene nanofluids. In this scientific article, the content had been carried out the encroachment of assessment and preparation techniques for the enhancement of graphene nanofluids.
Evaluation of a Refrigeration System Based on Nano-Refrigerants and Nano Lubricant
International Journal of Materials Engineering and Technology, 2021
This paper presents a summary of the influence of addition of nanoparticles to refrigerants as nano-refrigerants and to lubricants as nano-lubricants on the performance of refrigeration systems. Most of studies reported that disperse nanoparticles into refrigerants and lubricating oils lead to improve a coefficient of performance, due to improvement of thermal physics properties of a pure fluid, which leads to reduced energy consumption. Using nanoparticles in a refrigeration system is associated with many difficulties such as the cost of preparing and obtaining a stable and homogeneous mixture for a longer time with less agglomeration and sedimentation. We prepared nanoparticles in an inexpensive and easy way and in a mixture of copper and cerium oxides for the first time. Some studies have reported on the use of copper oxide and its effect on improving the performance of refrigeration system, but cerium oxide has not been used in refrigeration systems and this research aims to open the door to HudaElslam A. S. Mohamed and Unal Camdali 94 this oxide to know its characteristics, also to verify the possibility of overcoming the previously mentioned problems.