Application of hybrid nanofluid and a twisted turbulator in a parabolic solar trough collector: Energy and exergy models

Purpose This paper aims to present an analytical investigation of energy and exergy performance on a solar flat plate collector (SFPC) with Cu-CuO/water hybrid nanofluid, Cu/water and CuO/water nanofluids as collector running fluids. Design/methodology/approach Heat transfer characteristics, pressure drop and energy and exergy efficiencies of SFPC working on these nanofluids are investigated and compared. In this study, a comparison is made by varying the mass flow rates and nanoparticle volume concentration. Thermophysical properties of hybrid nanofluids are estimated using distinctive correlations available in the open literature. Then, the influence of these properties on energy and exergy efficiencies of SFPC is discussed in detail. Findings Energy analysis reveals that by introducing the hybrid nanoparticles in water, the thermal conductivity of the working fluid is enhanced by 17.52 per cent and that of the individual constituents is enhanced by 15.72 and 15.35 per cent for Cu/water and CuO/water nanofluids, respectively. This resulted in 2.16 per cent improvement in useful heat gain for hybrid nanofluid and 1.03 and 0.91 per cent improvement in heat gain for Cu/water and CuO/water nanofluids, respectively. In line with the above, the collector efficiency increased by 2.175 per cent for the hybrid nanofluid and 0.93 and 1.05 per cent enhancement for Cu/water and CuO/water nanofluids, respectively. Exergy analysis elucidates that by using the hybrid nanofluid, exergy efficiency is increased by 2.59 per cent, whereas it is 2.32 and 2.18 per cent enhancement for Cu/water and CuO/water nanofluids, respectively. Entropy generation is reduced by 3.31, 2.35 and 2.96 per cent for Cu-CuO/water, Cu/water and CuO/water nanofluids, respectively, as compared to water. Research limitations/implications However, this is associated with a penalty of increment in pressure drop of 2.92, 3.09 and 2.74 per cent for Cu-CuO/water, Cu/water and CuO/water nanofluids, respectively, compared with water. Originality/value It is clear from the analysis that Cu-CuO/water hybrid nanofluids possess notable increment in both energy and exergy efficiencies to use them in SFPCs.

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Energy and Exergy Analysis of Using Turbulator in a Parabolic Trough Solar Collector Filled with Mesoporous Silica Modified with Copper Nanoparticles Hybrid Nanofluid

Energies ◽

10.3390/en13112946 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2946 ◽

Cited By ~ 6

Author(s):

Sara Rostami ◽

Amin Shahsavar ◽

Gholamreza Kefayati ◽

Aysan Shahsavar Goldanlou

Keyword(s):

Energy Efficiency ◽

Solar Collector ◽

Thermal Characteristics ◽

Reynolds Numbers ◽

Research Area ◽

Hybrid Nanofluid ◽

Parabolic Trough ◽

Energy And Exergy ◽

Energy And Exergy Analysis ◽

Parabolic Trough Solar Collector

Designing the most efficient parabolic trough solar collector (PTSC) is still a demanding and challenging research area in solar energy systems. Two effective recommended methods for this purpose that increase the thermal characteristics of PTSCs are adding turbulators and nanofluids. To study the effects of the two approaches on the energy efficiency of PTSCs, a stainless steel turbulator was used and solid nanoparticles of Cu/SBA-15 were added to the water with the volume concentrations of 0.019% to 0.075%. The generated turbulence in the fluid flow was modeled by the SST k–ω turbulent model. The results in daylight demonstrated that energy efficiency increases steadily by 11:30 a.m., and then, starts to drop gradually due to more irradiations at noon. It was observed that applying the turbulator to the studied PTSC has a significant influence on the enhancement of energy efficiency. Adding the nanoparticles augmented the average Nusselt number inside the solar collector in various studied Reynolds numbers. It was also found that the increase in volume concentrations of nanoparticles enhances heat transfer regularly.

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NATURAL CONVECTION OF A HYBRID NANOFLUID-FILLED TRIANGULAR ANNULUS WITH AN OPENING

Computational Thermal Sciences An International Journal ◽

10.1615/computthermalscien.2016018833 ◽

2016 ◽

Vol 8 (6) ◽

pp. 555-566 ◽

Cited By ~ 4

Author(s):

Fatih Selimefendigil ◽

Ali J. Chamkha

Keyword(s):

Natural Convection ◽

Hybrid Nanofluid

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Energy and Exergy Efficiency of the Brazilian Passenger Vehicle Fleet – 1970-2017

10.26678/abcm.cobem2019.cob2019-1216 ◽

2019 ◽

Author(s):

Rafael Mosquim ◽

Carlos Eduardo Keutenedjian Mady

Keyword(s):

Exergy Efficiency ◽

Passenger Vehicle ◽

Energy And Exergy ◽

Vehicle Fleet

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Experimental Study on the Specific Heat Capacity Measurement of Water-Based Al2O3-Cu Hybrid Nanofluid by using Differential Thermal Analysis Method

Current Nanoscience ◽

10.2174/1573413715666191118105331 ◽

2019 ◽

Vol 15 ◽

Author(s):

Andaç Batur Çolak ◽

Oğuzhan Yıldız ◽

Mustafa Bayrak ◽

Ali Celen ◽

Ahmet Selim Dalkılıç ◽

...

Keyword(s):

Heat Capacity ◽

Specific Heat ◽

Specific Heat Capacity ◽

Thermophysical Properties ◽

Volume Concentration ◽

Pure Water ◽

Heat Capacity Measurement ◽

Experimental Results ◽

Hybrid Nanofluid ◽

Capacity Measurement

Background: Researchers working in the field of nanofluid have done many studies on the thermophysical properties of nanofluids. Among these studies, the number of studies on specific heat are rather limited. In the study of the heat transfer performance of nanofluids, it is necessary to increase the number of specific heat studies, whose subject is one of the important thermophysical properties. Objective: The authors aimed to measure the specific heat values of Al2O3/water, Cu/water nanofluids and Al2O3-Cu/water hybrid nanofluids using the DTA method, and compare the results with those frequently used in the literature. In addition, this study focuses on the effect of temperature and volume concentration on specific heat. Method: The two-step method was used in the preparation of nanofluids. The pure water selected as the base fluid was mixed with the Al2O3 and Cu nanoparticles and Arabic Gum as the surfactant, firstly mixed in the magnetic stirrer for half an hour. It was then homogenized for 6 hours in the ultrasonic homogenizer. Results: After the experiments, the specific heat of nanofluids and hybrid nanofluid were compared and the temperature and volume concentration of specific heat were investigated. Then, the experimental results obtained for all three fluids were compared with the two frequently used correlations in the literature. Conclusion: Specific heat capacity increased with increasing temperature, and decreased with increasing volume concentration for three tested nanofluids. Cu/water has the lowest specific heat capacity among all tested fluids. Experimental specific heat capacity measurement results are compared by using the models developed by Pak and Cho and Xuan and Roetzel. According to experimental results, these correlations can predict experimental results within the range of ±1%.

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