Numerical analysis of the influence of spherical turbulence generators on heat transfer enhancement of flat plate solar air heater

Manjunath, M; Karanth, K. Vasudeva; Sharma, Neha

doi:10.1016/j.energy.2017.01.032

Cited by 80 publications

(13 citation statements)

References 22 publications

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“…3b. The present numerical solution was validated by comparing the temperature distribution of absorber plate and water with the results of Manjunath et al [6]. The validation results show a very good agreement between the two investigations as shown in Fig.…”

Section: Grid Testing and Model Validationmentioning

confidence: 63%

“…It was found that edge effects must be significantly taken into consideration in order to derive more precise collector efficiency and heat loss coefficients as well as material costs. Karanth et al [5], Manjunath et al [6] and Selmi et al [7] carried out a 3D numerical investigation of a flatplate solar collector using Discrete Transfer Radiation (DTRM) with the help of Computational Fluid Dynamics (CFD) simulation method. It was seen that the water and absorber plate temperatures along flow length decreases with the increase of flow velocity and show similar linear trends for all the chosen velocities.…”

Section: Introductionmentioning

confidence: 99%

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Influence of nanofluids on the efficiency of Flat-Plate Solar Collectors (FPSC)

et al. 2017

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Abstract.A numerical investigation is performed using finite volume method to study the laminar heat transfer in a three-dimensional flat-plate solar collector using different nanofluids as working fluids. Three nanofluids with different types of nanoparticles (Ag, MWCNT and Al2O3 dispersed in water) with 1-2 wt% volume fractions are analyzed. A constant heat flux, equivalent to solar radiation absorbed by the collector, is applied at the top surface of the absorber plate. In this study, several parameters including boundary conditions (different volume flow rates, different fluid inlet temperatures and different solar irradiance at Skudai, Malaysia), different types of nanoparticles, and different solar collector tilt angles are investigated to identify their effects on the heat transfer performance of FPSC. The numerical results reveal that the three types of nanofluid enhance the thermal performance of solar collector compared to pure water and FPSC with Ag nanofluid has the best thermal performance enhancement. For all the cases, the collector efficiency increased with the increase of volume flow rate while fluid outlet temperature decreased. It is found that FPSC with tilt angle of 10° and fluid inlet temperature of 301.15 K has the best thermal performance.

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Section: Grid Testing and Model Validationmentioning

confidence: 63%

Section: Introductionmentioning

confidence: 99%

Influence of nanofluids on the efficiency of Flat-Plate Solar Collectors (FPSC)

et al. 2017

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“…5 In another work, Manjunath et al. 6 have improved the thermal efficiency of the SAC by about 26.5% using spherical turbulence generators. Similarly, the thermal efficiency of solar air collectors was improved by 26.5% using conical shaped protrusions placed over the absorber surface.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigations on jet impingement solar air collectors using pin-fin absorber

Kannan¹,

Mohanraj

Sathyabalan³

2020

Proceedings of the Institution of Mechanical Engineers, Part E:

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In this paper, the performances of a novel jet impingement solar air collector (JISAC) using flat and pin-fin absorbers were experimentally investigated. The experimental observations in a JISAC have been made under the climatic conditions of Coimbatore city in India during the year 2019. The thermo-hydraulic analyses were conduced to study the influence of pressure drop across the perforated jet plate. The effects of solar irradiation, ambient temperature, ambient wind velocity and air mass flow rate through the JISAC duct using flat and pin-fin absorbers were studied. The air mass flow rate through the JISAC was optimized to 0.025 kg/s based on the experimental trials. Thermodynamic performance comparisons have been made among the flat and pin-fin absorbers. The results showed that, the JISAC using pin-fin absorber has 2–7°C higher air temperature at the outlet with 3–7%, 2–6% and 2–6% improved energy efficiency, thermo-hydraulic efficiency and exergy efficiency, respectively when compared to the JISAC using flat absorber. The pressure drop across the JISAC duct is about 90% higher when compared to the conventional solar air collectors. The pressure drop through the jet plate has increased the air velocity impinging on the absorber. As a result, the heat transfer coefficient between air and the absorber has been significantly improved.

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“…The numerical study needs experiment validation to make the research result more reliable. In numerical study and experiment validation, Manjunath et al [13] investigated the effect of spherical turbulence generator on the efficiency of a solar air heater. They conducted simulations with various Reynolds numbers, sphere diameters and relative roughness pitch.…”

Section: Introductionmentioning

confidence: 99%

Validation and Numerical Sensitivity Study of Air Baffle Photovoltaic-Thermal Module

et al. 2020

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Photovoltaic-Thermal (PVT) is a type of technology that generates electricity and heat simultaneously at the point of use. The generated electricity could be used on site or exported to the grid while the thermal output could be utilized for space and water heating. There is a lot of research for solar air heating with experiment or CFD (Computational Fluid Dynamics), but CFD has the disadvantage that it would indicate impractical results. In this paper, a numerical PVT baseline model was developed and validated with Separate Effect Test (SET) data to increase reliability. The numerical study was conducted by considering the effect of baffle lengths and baffle slopes on outlet temperature, total heat transfer and pressure drop inside PVT air module. An optimum PVT baffle length and slope design were suggested. The baseline numerical PVT model agreed well with the test data set as indicated by 1.25% error for inlet–outlet temperatures difference. The sensitivity study was conducted by changing the PVT baffle length and slope. The optimum baffle design was concerned with both heat transfer and pressure drop at the same time with ratio. The baffle length should be kept under 150 mm and baffle slope should be greater than 30° to achieve better air mixing in PVT air channel and unit heat transfer compared to baffle slope less than 30°.

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Numerical analysis of the influence of spherical turbulence generators on heat transfer enhancement of flat plate solar air heater

Cited by 80 publications

References 22 publications

Influence of nanofluids on the efficiency of Flat-Plate Solar Collectors (FPSC)

Influence of nanofluids on the efficiency of Flat-Plate Solar Collectors (FPSC)

Experimental investigations on jet impingement solar air collectors using pin-fin absorber

Validation and Numerical Sensitivity Study of Air Baffle Photovoltaic-Thermal Module

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