scholarly journals Thermal Performance of Nanofluid Flow Inside Evacuated Tube Solar Collector

2021 ◽  
Vol 39 (4) ◽  
pp. 1262-1270
Author(s):  
Mohammad H. Yazdi ◽  
Evgeny Solomin ◽  
Ahmad Fudholi ◽  
Ghasem Divandari ◽  
Kamaruzzaman Sopian ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Solar Collector ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Pure Water ◽  
Radiant Energy ◽  
Solar Collectors ◽  
Nanofluid Flow ◽  
Ansys Fluent ◽  
Solar Radiation Incident

Solar collectors are systems for absorbing the sun's radiant energy and converting it into heat. The working principle of solar collectors are relying on the solar radiation incident upon the transparent surface, and the collected radiation heat is stored within the operating fluid. However, the conventional operating fluid is less than satisfactory in term of promoting the thermal efficiency of solar collector. Consequently, the aim of this paper is to investigate the use of nanofluid as an operating fluid in a single end evacuated solar collector. The expectation is that the flow behavior of nanofluid can lead to the improvement of thermal efficiency of solar collector. The design of solar collector is carried out using Gambit software and the heat transfer characteristics are simulated by nanofluid flow with 1%, 3% and 5% volumes by ANSYS Fluent software. The results demonstrate good agreement with existing experimental results. The numerical analysis shows the improvement of collector performance compared to pure water fluid. The results show that by increasing the nanoparticles volume fraction the efficiency of the collector improves significantly.

Solar Energy Harvesting Using Nanofluids-Based Concentrating Solar Collector

2012 ◽  
Author(s):  
Vikrant Khullar ◽  
Himanshu Tyagi ◽  
Patrick E. Phelan ◽  
Todd P. Otanicar ◽  
Harjit Singh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Solar Collector ◽  
Base Fluid ◽  
Incident Angle ◽  
Convective Heat Transfer Coefficient ◽  
Radiant Energy ◽  
Absorption Capacity ◽  
Solar Collectors ◽  
Solar Insolation ◽  
Solar Energy Harvesting

Dispersing trace amounts of nanoparticles into the base-fluid has significant impact on the optical as well as thermo-physical properties of the base-fluid. This characteristic can be utilized in effectively capturing as well as transporting the solar radiant energy. Enhancement of the solar irradiance absorption capacity of the base fluid scales up the heat transfer rate resulting in higher & more efficient heat transfer. This paper attempts to introduce the idea of harvesting the solar radiant energy through usage of nanofluid-based concentrating parabolic solar collectors. In order to theoretically analyze the nanofluid-based concentrating parabolic solar collector (NCPSC) it has been mathematically modeled, and the governing equations have been numerically solved using finite difference technique. The results of the model were compared with the experimental results of conventional concentrating parabolic solar collectors under similar conditions. It was observed that while maintaining the same external conditions (such as ambient/inlet temperatures, wind speed, solar insolation, flow rate, concentration ratio etc.) the NCPSC has about 5–10% higher efficiency as compared to the conventional parabolic solar collector. Furthermore, some parametric studies were carried out which reflected the effect of various parameters such as solar insolation, incident angle, convective heat transfer coefficient etc. on the performance indicators such as thermal efficiency etc.

Applicability of Heat Mirrors in Reducing Thermal Losses in Concentrating Solar Collectors

2016 ◽  
Author(s):  
Prashant Mahendra ◽  
Vikrant Khullar ◽  
Madhup Mittal
Keyword(s):  
Heat Transfer ◽  
Thermal Efficiency ◽  
Solar Irradiance ◽  
Solar Collector ◽  
Flux Distribution ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
Solar Collectors ◽  
Parabolic Trough ◽  
Glass Envelope

Flux distribution around the parabolic trough receiver being typically non-uniform, only a certain portion of the receiver circumference receives the concentrated solar irradiance. However, radiative and convective losses occur across the entire receiver circumference. This paper attempts to introduce the idea employing transparent heat mirror to effectively reduce the heat loss area and thus improve the thermal efficiency of the solar collector. Transparent heat mirror essentially has high transmissivity in the solar irradiance wavelength band and high reflectivity in the mid-infrared region thus it allows the solar irradiance to pass through but reflects the infrared radiation back to the solar selective metal tube. Practically, this could be realized if certain portion of the conventional low iron glass envelope is coated with Sn-In2O3 so that its acts as a heat mirror. In the present study, a parabolic receiver design employing the aforesaid concept has been proposed. Detailed heat transfer model has been formulated. The results of the model were compared with the experimental results of conventional concentrating parabolic trough solar collectors in the literature. It was observed that while maintaining the same external conditions (such as ambient/initial temperatures, wind speed, solar insolation, flow rate, concentration ratio etc.) the heat mirror-based parabolic trough concentrating solar collector has about 3–12% higher thermal efficiency as compared to the conventional parabolic solar collector. Furthermore, steady state heat transfer analysis reveals that depending on the solar flux distribution there is an optimum circumferential angle (θ = θoptimum, where θ is the heat mirror circumferential angle) up to which the glass envelope should be coated with Sn-In2O3. For angles higher than the optimum angle, the collector efficiency tends to decrease owing to increase in optical losses.

scholarly journals An Investigation of the Effect of Different Nanofluids in a Solar Collector

2017 ◽  
Vol 7 (4) ◽  
pp. 1741-1745
Author(s):  
H. A. Fakhim
Keyword(s):  
Thermal Efficiency ◽  
Solar Collector ◽  
Concentration Ratio ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Average Temperature ◽  
Nano Fluid ◽  
Parabolic Form ◽  
Parabolic Collector

In this article, we examine the use of different nanofluids in a solar collector in a parabolic form. Temperature, thermal efficiency and outlet average temperature for a conventional parabolic collector and a collector with nanofluid are compared. The effect of various parameters (concentration ratio, volume fraction of nanoparticles, absorption and fluid velocity) are studied. Results are discussed and it is shown that nano fluid increases the efficiency of the collector.

scholarly journals Numerical simulation of thermal efficiency of an innovative Al2O3 nanofluid solar thermal collector: Influence of nanoparticles concentration

2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2769-2779 ◽  
Author(s):  
Gianpiero Colangelo ◽  
Marco Milanese ◽  
Risi de
Keyword(s):  
Thermal Efficiency ◽  
Volume Fraction ◽  
Pure Water ◽  
Weather Conditions ◽  
Solar Thermal ◽  
Working Fluid ◽  
Al2o3 Nanoparticles ◽  
Solar Thermal Collector ◽  
Nanoparticles Concentration ◽  
Al2o3 Nanofluid

Investigations on the potential thermal efficiency of an innovative nanofluid solar thermal collector have been performed using a commercial software (RadTherm ThermoAnalytics rel. 10.5). The Al2O3-nanofluid has been simulated as working fluid of the solar thermal collector, varying the nanoparticles concentration from 0%vol of Al2O3 nanoparticles (pure water) up to 3%vol of Al2O3 of nanoparticles. The numerical model has been validated with experimental data, obtained with a real prototype of the simulated solar thermal collector. Real thermal properties of the nanofluids at different concentrations have been used in the simulations. The boundary conditions used for the simulations have been those of real weather conditions. An increase in thermal efficiency (up to 7.54%) has been calculated using nanofluid with a volume fraction of 3% and the influence of nanoparticles concentration on the thermal performance of the solar collector has been pointed out.

scholarly journals Improving the Thermal Efficiency of Flat Plate Solar Collector Using Nano-Fluids as a Working Fluids: A Review

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Saif Ali Kadhim ◽  
Osama Abd AL-Munaf Ibrahim
Keyword(s):  
Flat Plate ◽  
Thermal Efficiency ◽  
Solar Collector ◽  
Base Fluid ◽  
Working Fluid ◽  
Solar Collectors ◽  
Nano Fluid ◽  
Flat Plate Solar Collector ◽  
Nano Fluids ◽  
Better Than

Solar energy is one of the most important types of renewable energy and is characterized by its availability, especially in Iraq. It can be used in many applications, including supply thermal energy by solar collectors. Improving the thermal efficiency of solar collector leads to an increase in the thermal energy supplied. Using a nano-fluid instead of base fluid (water is often used) as a working fluid is a method many used to increase the thermal efficiency of solar collectors. In this article, the latest research that used nano-fluid as a working fluid in evaluating the thermal efficiency of solar collector, type flat plate was reviewed. The thermal efficiency improvement of flat plate solar collector was reviewed based on the type of nanoparticles (metal oxides, semiconductors oxides, carbon compounds) used in the base fluid and comparison was made between these nanoparticles under the same conditions. Moreover, the effect of varying the concentration of nanoparticles in the base fluid and changing the working fluid flow rate on the thermal efficiency of flat plate solar collector was also reviewed. The results of the review showed that nano-fluids containing carbon compounds are better than other nano-fluids and that copper oxide is better than the rest of the metal oxides used in improving the thermal efficiency of flat plate solar collectors.

scholarly journals Thermally Fully Developed Electroosmotic Flow of Power-Law Nanofluid in a Rectangular Microchannel

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 363 ◽  
Author(s):  
Shuyan Deng
Keyword(s):  
Nusselt Number ◽  
Thermal Behavior ◽  
Power Law ◽  
Electroosmotic Flow ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Nanoparticle Volume Fraction ◽  
Nanofluid Flow ◽  
Rectangular Microchannel ◽  
Power Law Nanofluid

The hydrodynamic and thermal behavior of the electroosmotic flow of power-law nanofluid is studied. A modified Cauchy momentum equation governing the hydrodynamic behavior of power-law nanofluid flow in a rectangular microchannel is firstly developed. To explore the thermal behavior of power-law nanofluid flow, the energy equation is developed, which is coupled to the velocity field. A numerical algorithm based on the Crank–Nicolson method and compact difference schemes is proposed, whereby the velocity, temperature, and Nusselt number are computed for different parameters. A larger nanoparticle volume fraction significantly reduces the velocity and enhances the temperature regardless of the base fluid rheology. The Nusselt number increases with the flow behavior index and with electrokinetic width when considering the surface heating effect, which decreases with the Joule heating parameter. The heat transfer rate of electroosmotic flow is enhanced for shear thickening nanofluids or at a greater nanoparticle volume fraction.

The Effect of using different Nano fluids on Heat Transfers through Flat Plate Solar Collector

2018 ◽  
Vol 6 (2) ◽  
pp. 46-55
Author(s):  
Abbas Sahi Shareef ◽  
Zahraa Basim Abdel-Mohsen
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Solar Collector ◽  
Volume Fraction ◽  
Pure Water ◽  
High Heat ◽  
Working Fluid ◽  
High Heat Transfer ◽  
Flat Plate Solar Collector ◽  
Heat Transfers

In this paper investigation experimentally the effect of CuO-water and Al2O3/water nanofluids on heat transfer in flat plate solar collector. The volume fraction was used (0.125,0.25 and 0.5) % for flow flow rate of working fluid equal to (1 L/min) and the particles size was 20 nm. The experiments are conducted in Kerbala, Iraq with the latitude of 32.60 N. The result shows that the maximum outlet-inlet temperatures difference obtained at (0.5 vol. %) nanofluid are (16.2 0C) for (Al2O3/water), (15.5 0C) for (CuO/water) nanofluid, and (10.2 0C) for pure water. Also, Al2O3 shows high heat transfer compared to CuO, this lead to improve the performance of the solar fat-plate collector.

scholarly journals The Influence of Inflow Swirl on Cavitating and Mixing Processes in a Venturi Tube

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 170
Author(s):  
Hongbo Shi ◽  
Petr Nikrityuk
Keyword(s):  
Pressure Drop ◽  
Volume Fraction ◽  
Pure Water ◽  
Swirl Flow ◽  
Linear Increase ◽  
Venturi Tube ◽  
Fluid Viscosity ◽  
Multiphase Model ◽  
Mixing Processes ◽  
Ansys Fluent

A study of the mixing flows (Schmidt number = 103) in a cavitating Venturi tube that feature linear and swirling flows is presented in this paper. The Large Eddy Simulation (LES) turbulence model, the Schnerr–Sauer cavitation model, and the mixture multiphase model, as implemented in the commercial CFD ANSYS FLUENT 16.2, were employed. The main emphasis is spending on the influence of different inlet swirling ratios on the generation of cavitation and mixing behaviors in a Venturi tube. Four different inflow regimes were investigated for the Reynolds number Re = 19,044, 19,250, 19,622, 21,276: zero swirl, 15% swirl, 25% swirl and 50% swirl velocity relative to the transverse inflow velocity, respectively. The computed velocity and pressure profiles were shown in good agreement with the experiment data from the literature. The predicted results indicate that the imposed swirl flow moves the cavitation bubbles away from throat surfaces toward the throat axis. The rapid mixing between two volumetric components is promoted in the divergent section when the intense swirl is introduced. Additionally, the increase in the swirl ratio from 0.15 to 0.5 leads to a linear increase in the static pressure drop and a nonlinear increase in the vapor production. The reduction in the fluid viscosity ratio from μ2μ1=10 to μ2μ1=1 generates a high cavitation intensity in the throat of the Venturi tube. However, the changes in the pressure drop and vapor volume fraction are significantly small of pure water flow.

Solar Energy Harvesting Using Nanofluids-Based Concentrating Solar Collector

2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Vikrant Khullar ◽  
Himanshu Tyagi ◽  
Patrick E. Phelan ◽  
Todd P. Otanicar ◽  
Harjit Singh ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Solar Collector ◽  
Incident Angle ◽  
Convective Heat Transfer Coefficient ◽  
Radiant Energy ◽  
Absorption Capacity ◽  
Solar Collectors ◽  
Solar Insolation ◽  
Solar Energy Harvesting ◽  
Efficient Heat Transfer

Dispersing trace amounts of nanoparticles into common base-fluids has a significant impact on the optical as well as thermophysical properties of the base-fluid. This characteristic can be utilized to effectively capture and transport solar radiation. Enhancement of the solar irradiance absorption capacity leads to a higher heat transfer rate resulting in more efficient heat transfer. This paper attempts to introduce the idea of harvesting solar radiant energy through usage of nanofluid-based concentrating parabolic solar collectors (NCPSC). In order to theoretically analyze the NCPSC, it has been mathematically modeled, and the governing equations have been numerically solved using finite difference technique. The results of the model were compared with the experimental results of conventional concentrating parabolic solar collectors under similar conditions. It was observed that while maintaining the same external conditions (such as ambient/inlet temperatures, wind speed, solar insolation, flow rate, concentration ratio, etc.) the NCPSC has about 5–10% higher efficiency as compared to the conventional parabolic solar collector. Furthermore, parametric studies were carried out to discover the influence of various parameters on performance and efficiency. The following parameters were studied in the present study: solar insolation, incident angle, and the convective heat transfer coefficient. The theoretical results clearly indicate that the NCPSC has the potential to harness solar radiant energy more efficiently than a conventional parabolic trough.

A Comparative Study on Thermal-Hydraulic Performance of Different Non-Newtonian Nanofluids Through an Elliptical Annulus

2021 ◽  
Vol 13 (5) ◽  
Author(s):  
Prabhakar Zainith ◽  
Niraj Kumar Mishra
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Base Fluid ◽  
Volume Fraction ◽  
Flow Behavior ◽  
Pure Water ◽  
Reynolds Numbers ◽  
Power Law Model ◽  
Laminar Condition

Abstract This paper presents a numerical investigation on heat transfer and flow behavior for non-Newtonian nanofluids with different nanoparticles (Al2O3 and CuO) and carboxymethyl cellulose (CMC) with water as a base fluid. The analysis has been carried out in an elliptical tube. Power-law model is adopted to depict the non-Newtonian nature of nanofluid. The present study has been done with a range of nanosized particles 0–4% by volume, and the variation of Reynolds number is kept under the laminar condition. The physical model covers two concentric tubes used to create an annular space. The effects of volume fraction, particle type, and base fluid have been investigated at different Reynolds numbers numerically. Also, the effect of pressure and heat transfer coefficient on the flow behavior of non-Newtonian nanofluids is analyzed. The results concluded that Al2O3 particles showed 219% and CuO particles give 195% higher heat transfer coefficient as compared with pure water.

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