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Refrigerant temperature gain across the evaporator for refrigerant flow rate 11 L/h at: (a) 21 CAE1 C; (b) 28 C AE 1 C ambient temperature.
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An attempt has been made to improve the heat transfer characteristics of the vapor compression refrigeration cycle using nanorefrigerant (R134a and Al 2 O 3 , size 20 nm). The performance parameters such as, coefficient of performance, cooling capacity, energy consumption, and temperature drop across condenser and evaporator have been investigated...
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Citations
... Nanorefrigerants are a combination of refrigerants and nanoparticles that are specifically designed for heat transfer purposes. The use of nanorefrigerants/nanolubricants improved system performance and efficiency while lowering energy consumption [9][10][11]. The single-step technique, which involves the simultaneous formation and dispersion of nanoparticles in the base fluid [12], and the two-step technique, which involves the dispersion of the nanoparticles directly in the refrigerant or lubricant [13], are used to prepare nanorefrigerants and nanolubricants. ...
Waste management has been a major concern in the society and agricultural wastes can be utilized in the synthesis of nanoparticles and deployed in the vapour compression refrigeration system (VCRS) to enhance its performance. This study analysed the thermophysical properties, performance, energy consumption, pull-down time, and capacities of VCRS using bio-nanoparticles produced from orange and pineapple peels. Eco-friendly refrigerants R600a and R134a with pure polyolester (POE) as the lubricating oil for the compressor were used. The nanolubricants were dispersed in three volume fractions of 0.05%, 0.10% and 0.20% concentration in the lubricant using the two-step method. The degradation of nanolubricants were analysed by examining the thermophysical properties of the nanolubricants before and after use in the VCRS. At 0.2% volume concentration, optimum COP of 6.31 and 5.01 were obtained for pineapple and orange peels respectively for R600a. The nanolubricants of orange peels with the volume fraction of 0.2% had the best pull-down time with a temperature of-2oC. The lowest power consumption was observed for 0.1% volume concentration of pineapple nanolubricants while 0.2% volume concentration of orange nanolubricants was observed to have the least power consumption. Considering the R134a refrigerant, the volume concentration with the optimum COP was 0.1 vol% concentration for the orange bio-based nanolubricants with an increase in the COP of 36.3% when compared with pure R134a while 0.2 vol% had the best pull-down time with a temperature of-3oC. There was a 14.2% drop in the power consumption of 0.1 vol% concentration of pineapple nanolubricants when compared to the various concentrations of the bio-based nanolubricants. From this study, the optimum performance was observed at 0.20 vol% concentration for the orange and pineapple nanolubricants with a relatively less power consumption. R600a refrigerant can completely replace R134a in its use in refrigeration systems and achieve similar pull-down time and coefficient of performance when bio-nanolubricants are utilized in the systems.
... and the temperature decrease in the condenser (3.0%e23.77%) have also been noticed for the refrigerating device in time investigation [38]. Recently, it has been observed that the nanoparticle dimension has no significant effect on the capability of the refrigerating device at the lower nanoparticle volume percentage and the overall refrigeration system performance deteriorates beyond a certain volume concentration of nanoparticle [39]. ...
... The results were analysed using Simulink model and the heat transfer characteristics of nanoparticles was observed to be optimal at a lower concentration of 0.1%. Kundan and Singh (2020) studied the influence of volume flow rate on the COP, cooling capacity and energy consumption of the VCRS using Al2O3/R134a nanorefrigerant with nanoparticle size of 20 nm and mass concentration between 0.5% and 1%. The study observed that an increase in the volume flow rate of nanorefrigerant improved that COP and the cooling capacity of the VCRS. ...
Hydrochlorofluorocarbon and chlorofluorocarbon refrigerants commonly used in vapour compression refrigeration system (VCRS) have been phased out due to their negative impact on the ecosystem. R134a and R600a refrigerants were considered as their replacement, but they possess low thermal properties, thereby affecting the performance of the VCRS. In this study, the effect of varying aluminium oxide (Al2O3) nanoparticle size (10 nm, 20 – 30 nm and 80nm) and volume concentration (1%, 3%, 5% 10% and 20%) on the capacity and exergy efficiency of each component of VCRS for the optimisation of the VCRS performance and reduction of energy consumption was analysed using R134a and R600a refrigerants. The nanolubricant were prepared using the two-step method. The VCRS showed no significant deterioration in the performance of its components as confirmed for over 24 hours when nanorefrigerant was used. The compressor capacity of nanorefrigerant was lower than that of pure refrigerants while the addition of nanoparticle enhanced the refrigeration effect. The exergy efficiency of the vapour compression system improved with the addition of nanoparticles into the system, the exergy destruction caused by friction in the compressor significantly reduced, thereby reducing the energy consumed by the system.
... The nanorefrigerant has improved thermal properties and heat transfer properties, when compared to the base refrigerant 6,7 . Their use in VCRS leads to higher cooling capacities and gain in their performance 8,9,10 . In the light of the above arguments, nanorefrigerants are seen to be the future refrigerants working in VCRS 10 . ...
... The results showed that the time was reduced using a 0.1% fraction of nanorefrigerant and this reduction in time increases the cooling capacity of the unit. Kundan and Singh [139] studied Al 2 O 3 nanoparticles in the R134a cooling cycle and reported that the cooling capacity of the refrigerating unit had been improved at an atmospheric temperature of 21 °C. Pico et al. [140] mixed diamond nanoparticles at 0.1 and 0.5 Vol. ...
Nowadays, nanorefrigerants have been focused across the globe to improve the heat transfer characteristics of cooling units. Incorporating high thermal conductivity nanoparticles to the conventional refrigerants presented broad facts such as increased heat transfer coefficients, improved pool boiling inside closed cycles, enhanced COP, reduced compressor energy consumption of domestic refrigerators, and enhanced heat transfer rate during the two-phase flow of fluids. The present article focused on comprehensive experimental and numerical research reports of nanorefrigerants and nanolubricants. The heat and mass transfer and thermophysical characters such as viscous behavior, thermal conductivity, specific heat, and density have been discussed for various facts like flow condensation of fluids, evaporation, refrigerants pool boiling, and other related processes. The results showed that the volume concentration, diameter, and length of particles have a significant and crucial impact on the heat transfer rate and characteristics of pure refrigerants. Based on the available reports, it can say that the application of nanoparticles in pure refrigerants may enhance its features by about 50 – 60%. Further, the proposed correlations available in the literature for nanorefrigerants have been well discussed.
... The COP of Ag-doped nano-CuO increased up to 29 %, while the power consumption of a system reduced up to 28 %. Kundan and Singh [30] evaluated the performance of a vapour compression refrigeration system based on nano-refrigerant consisting of 0.5 wt.% to 1 wt.% Al 2 O 3 dispersed into R134a, with a particle size diameter of 20 nm The results based on volume flow rates of refrigerants showed that 6.5 l/h and 11 l/h achieved improvements of COP from 7.20 % to 16.34 % respectively at 0.5 wt.% Al 2 O 3 ; however, 1 wt.% ...
Most studies report that dispersing nanoparticles into refrigerants and lubricating oils leads to performance improvements in refrigeration systems, due to improvements in the thermal physics properties of a pure refrigerant, 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 with less agglomeration and sedimentation. Most current studies focus on the use of metals, metal oxides, and a hybrid of oxides as nanoparticles in refrigeration systems. In this research, nanoparticles were prepared in an inexpensive and easy way as a single oxide and as a mixture consisting of copper and cerium oxides. The results of nanoparticle preparation using X-ray diffraction and scanning electron microscopy prove that the particles of the samples were spherical in shape, with suitable average diameters ranging from 78.95 nm, 79.9 nm, 44.15 nm and 63.3 nm for copper oxide, cerium oxide, the first mixture, and the second mixture, respectively. Cerium oxide has not been used in a refrigeration system; this study preferred the implementation of a theoretical study using Ansys Fluent software to verify the possibility of improving the performance of the refrigeration system. The results confirmed that copper oxide enhanced the coefficient of performance of the refrigeration system by 25 %, and cerium oxide succeeded in improving the performance of the. system by a lesser value. The mixture containing a higher percentage of copper oxide yielded better results.
... The COP of Ag-doped nano-CuO increased up to 29%, while the power consumption of a system reduced up to 28%. Kundan and Singh [27] evaluated the performance of VCRS based on nano-refrigerant consisting of 0.5 to 1 wt% of Al 2 O 3 are dispersed into R134a, particle size diameter 20 nm the results based on volume flow rates of refrigerants showed that 6.5 L/h and 11 L/h achieved improvements of COP from 7.20 to 16.34%, respectively, at 0.5 wt% of Al 2 O 3 . However, applied 1 wt. ...
This study was built on the basis of an experimental study that was carried out on a simple refrigeration system that works with R134a as a refrigerant, and based on the real dimensions of the system and the experimental results, the Ansys fluent software was used to simulate the system to prepare the system to introduce the nanoparticles theoretically. Since the nanoparticles preparation process is expensive, this research presents a simple, easy, and inexpensive method for the preparation process based on the following materials, distilled water, ammonia, copper nitrate, and cerium nitrate to synthesize seven types of nanoparticles as a single oxide and as a mixture from two different oxides The results of preparing using X-Ray Diffraction and Scanning Electron Microscopy proved that particles of samples were spherical in shape, with suitable average diameter ranging between 78.95, 79.9, 44.15 and 63.3 nm for both copper oxide, cerium oxide, first mixture, and second mixture, respectively, the theoretical study confirmed that both copper oxide, cerium oxide, and the mixture consisting of both improved the performance of the refrigeration system and reduced energy consumption.
... Further, several studies have been performed on R134a refrigerant as the mostly used refrigerant. Kundan and Singh (2021) performed an investigation on the vapour compression refrigeration system using Al 2 O 3 /R134a nanorefrigerant. It was reported that the COP of a refrigeration system was enhanced by 7.2 and 16.3% at volume flow rates of 6.5 and 11 L/h, respectively, while using 0.5 wt% Al 2 O 3 /R134a refrigerant. ...
Household energy consumption increases day by day because of the civilization and luxury life. In case of household refrigerator, the compressor consumes more energy. There is possibility to reduce the compressor work by increasing the heat transfer rate of refrigerant using nano-additives. Hence, the aim of the present work is to improve the performance of the household refrigerator using nano-additive refrigerant. Ceria nanoparticles (CeO2) have the potential to transfer more heat as it has higher thermal conductivity. In this research work, four types of refrigerant were prepared namely R0 (R134a), R1 (R134a + 0.05 vol% CeO2), R2 (R134a + 0.10 vol% CeO2) and R3 (R134a + 0.15 vol% CeO2) and the performance of the household refrigerator was studied using the aforementioned refrigerants. Experimental results showed that the thermal conductivity of R0 improved with the addition of CeO2 and the R3 refrigerant displayed the higher thermal conductivity of 0.057 W/mK. Further, the COP of the refrigeration system was greatly improved when using R3 (R134a + 0.15 vol% CeO2) refrigerant, which is 7.6% greater than the COP of R0 refrigerant. Moreover, the suction and delivery characteristics were enhanced while using CeO2 blended refrigerant. The results show the R3 refrigerant had the lowest compression ratio of 4.4, which was 6.03% lower than the compression ratio of R0 refrigerant. In addition, a significant enhancement in volumetric and isentropic efficiency was observed as 91.53 and 61.98%, respectively.
... The COP of Ag-doped nano-CuO increased up to 29%, while the power consumption of a system reduced up to 28%, (Manikanden and Avinash, 2019). Kundan and Singh (2021) evaluated the performance of VCRs based on nano-refrigerant consisting of 0.5 to 1 wt.% of Al2O3 are dispersed into R134a, particle size diameter 20 nm. The results based on volume flow rates of refrigerants showed that 6.5 L/h and 11 L/h achieved improvements of COP from7.20 % to 16.34% respectively at 0.5 wt.% of Al2O3. ...
... The results based on volume flow rates of refrigerants showed that 6.5 L/h and 11 L/h achieved improvements of COP from7.20 % to 16.34% respectively at 0.5 wt.% of Al2O3. However, applied 1 wt.% of Al2O3 caused reduction of COP at the same volume flow rates (Kundan and Singh, 2021). Nagaraju and Reddy (2018) evaluated the performance of VCRs based on nano-refrigerants consisting of 0.05 to 0.8 wt.% of CuO particle size range 10 to 70 nm is dispersed into R134a. ...
... There are many applications in which nanofluids can play a significant enhancement role in their performance. Examples of such include medical applications (Saleh et al., 2017), liquid fuels combustion enhancement , air purification systems (Yang et al., 2020a,b), quenching media Ramadhani et al., 2019), magnetic sealing , nanolubricants , heat exchangers working fluid (Almurtaji et al., 2020), air conditioning and refrigeration systems (Kundan and Singh, 2020), gas turbine intercooler (Alsayegh and Ali, 2020), and many more. ...
It is well understood that waste or scrap is a by-product of daily activities and social behavior. Waste could originate from various sectors and encompasses various components that renders it quite attractive to valorize and develop various valuable products out of. Waste could originate from industrial sectors that render it hard to classify, such as the case in end-of-life tires or industrial scrap. Both of which contain a hefty proportion of metallic fractions that make them quite attractive to reuse. To put things into a better perspective, the Oxford English Dictionary defines scrap as “odds and ends, leavings; waste material.” For hundreds of years, waste materials were viewed as undesired substances that must be disposed of after their primary use. Recycling in modern societies has received great attention since it provides the means for generating value from scrap materials. This chapter aims to provide a critical insight on the challenge of sustainable development that has been started from the last century, dedicated to develop cost-effectiveness processes for metallic-based recycles. It will also discuss the current technologies employed for metal recovery and recycling from waste to high purity metallic feedstock production, that can be used in both traditional and high-tech applications. Here we will focus on the recycling of iron (Fe) and copper (Cu) metals and their alloys, originating from various sectors. Moreover, a detailed discussion on the new applications of the recycled metals in different sectors will be provided. This chapter will also present research insights and case studies of metal recycling and their advanced applications. This chapter provides a Birdseye view of possible integrated waste management holistic approaches that can render such metallic waste of high end value to the chain of waste management.
