Numerical Analysis of Flat Plate Solar Air Heater Integrated With an Array of Pin Fins on Absorber Plate for Enhancement in Thermal Performance

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
M. S. Manjunath ◽  
K. Vasudeva Karanth ◽  
N. Yagnesh Sharma
Keyword(s):  
Numerical Analysis ◽  
Flat Plate ◽  
Flow Rate ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Pin Fin ◽  
Pin Fins ◽  
Effective Efficiency ◽  
Pin Fin Array ◽  
Lower Flow Rate

This paper presents a three-dimensional numerical analysis of a flat plate solar air heater in the presence of a pin fin array using the computational fluid dynamics (CFD) software tool ansys fluent 16.2. The effect of geometric parameters of pin fins as well as the flow Reynolds number (4000–24,000) on the effective efficiency is evaluated. The longitudinal pitch (PL) of pin fin array is varied as 30 mm, 40 mm, and 50 mm and the diameter (Dw) is varied as 1.0 mm, 1.6 mm, and 2.2 mm. The results show that the presence of pin fins generate considerable enhancement in fluid turbulence as well as heat transfer area to a maximum extent of about 53.8%. The maximum average increase in instantaneous thermal efficiency is found to be about 14.2% higher as compared with the base model for the fin diameter of 2.2 mm and a longitudinal pitch value of 30 mm. In terms of effective efficiency, the pin fin array exhibits significant enhancement, especially at lower flow rate conditions. Finally, the effective efficiency of the pin fin array is compared with the previous work of authors involving spherical turbulators and sinewave corrugations on the absorber plate. The results show that the pin fin array exhibits a relatively superior effective efficiency to a maximum extent of about 73% for lower flow rate conditions.

scholarly journals Effect of Parametric Uncertainties, Variations, and Tolerances on Thermohydraulic Performance of Flat Plate Solar Air Heater

2014 ◽  
Vol 2014 ◽  
pp. 1-18 ◽  
Author(s):  
Rajendra Karwa ◽  
Shweta Baghel
Keyword(s):  
Flat Plate ◽  
Flow Rate ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Solar Insolation ◽  
Black Paint ◽  
Selective Coating ◽  
Air Heater ◽  
Sky Temperature ◽  
Winter Operation

The paper presents results of an analysis carried out using a mathematical model to find the effect of the uncertainties, variations, and tolerances in design and ambient parameters on the thermohydraulic performance of flat plate solar air heater. Analysis shows that, for the range of flow rates considered, a duct height of 10 mm is preferred from the thermohydraulic consideration. The thermal efficiency changes by about 2.6% on variation in the wind heat transfer coefficient, ±5 K variation in sky temperature affects the efficiency by about ±1.3%, and solar insolation variation from 500 to 1000 Wm−2 affects the efficiency by about −1.5 to 1.3% at the lowest flow rate of 0.01 kgs−1 m−2 of the absorber plate with black paint. In general, these effects reduce with increase in flow rate and are lower for collector with selective coating on the absorber plate surface. The tolerances in the duct height and absorber plate emissivity should be small while positive tolerance of 3° in the collector slope for winter operation and ±3° for year round operation, and a positive tolerance for the gap between the absorber plate and glass cover at nominal value of 40 mm are recommended.

Numerical analysis of a solar air heater with circular perforated absorber plate

Solar Energy ◽  
2021 ◽  
Vol 215 ◽  
pp. 416-433
Author(s):  
Shreyas P. Shetty ◽  
N. Madhwesh ◽  
K. Vasudeva Karanth
Keyword(s):  
Numerical Analysis ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Air Heater

Energy and Exergy Analysis of Marquise Shaped Channel Flat Plate Solar Collector Using Al2O3–Water Nanofluid and Water

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Sahil Arora ◽  
Geleta Fekadu ◽  
Sudhakar Subudhi
Keyword(s):  
Flat Plate ◽  
Flow Rate ◽  
Volume Fraction ◽  
Pure Water ◽  
Maximum Energy ◽  
Working Fluid ◽  
Absorber Plate ◽  
Energy And Exergy ◽  
Aluminum Plates ◽  
Flat Plate Collector

The present study deals with the experimental performance of a Marquise shaped channel solar flat-plate collector using Al2O3/water nanofluid and base fluid (pure water). The experimental setup comprises a special type of solar flat plate collector, closed working fluid systems, and the measurement devices. The absorber plate is made of two aluminum plates sandwiched together with Marquise-shaped flow channels. The volume fraction of 0.1% of Al2O3/water nanofluid is used for this study. The various parameters used to investigate performance of the collector energy and exergy efficiency are collector inlet and outlet fluid temperatures, mass flow rate of the fluid, solar radiation, and ambient temperature. The flow rate of nanofluid and water varies from 1 to 5 lpm. The maximum energy efficiencies attained are 83.17% and 59.72%, whereas the maximum exergy efficiencies obtained are 18.73% and 12.29% for the 20 nm—Al2O3/water nanofluids and pure water, respectively, at the flow rate of 3 lpm. These higher efficiencies may be due to the use of nanofluids and the sophisticated design of the absorber plate with the Marquise shaped channel.

Numerical Study of the Endwall Effects on Water Single-Phase Pressure Drop Across a Circular Micro-Pin-Fin Array

2011 ◽  
Author(s):  
Jonathan R. Mita ◽  
Weilin Qu ◽  
Frank E. Pfefferkorn
Keyword(s):  
Pressure Drop ◽  
Single Phase ◽  
Numerical Study ◽  
Circular Cross Section ◽  
Reynolds Numbers ◽  
Pin Fin ◽  
Pin Fins ◽  
Micron Diameter ◽  
Micro Pin Fins ◽  
Pin Fin Array

This paper presents a numerical study of pressure drop associated with water liquid single-phase flow across an array of staggered micro-pin-fins having circular cross-section. The numerical simulations were validated against previously obtained experimental results using an array of staggered circular micro-pin-fins having the following dimensions: 180 micron diameter and 683 micron height. The longitudinal pitch and transverse pitch of the micro-pin-fins are equal to 399 microns. The effects of endwalls on pressure drop characteristics were then explored numerically. Six different micro-pin-fin height to diameter ratios were studied with seven different Reynolds numbers. All simulations were performed at room temperature (23°C). It was seen that for any given Reynolds number, as the pin height to diameter ratio increased, the pressure drop and resulting non-dimensional friction factor decreased.

scholarly journals Experimental Studies on a Solar Air Heater Having V-Corrugated Absorber Plate with Obstacles Bent Vertically

2014 ◽  
Vol 493 ◽  
pp. 86-92 ◽  
Author(s):  
Ekadewi A. Handoyo ◽  
Djatmiko Ichsani ◽  
Prabowo ◽  
S. Sutardi
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flat Plate ◽  
Air Temperature ◽  
Temperature Rise ◽  
Experimental Studies ◽  
Bottom Plate ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Air Heater

A solar air heater (SAH) is a simple heater using solar radiation that is useful for drying or space heating. Unfortunately, heat transfer from the absorber plate to the air inside the solar air heater is low. Some researchers reported that obstacles are able to improve the heat transfer in a flat plate solar air collector and others found that a v-corrugated absorber plate gives better heat transfer than a flat plate. Yet, no work of combining these two findings is found.This paper describes the result of experimental study on a SAH with v-corrugated absorber plate and obstacles bent vertically started from 80oto 0owith interval 10oon its bottom plate. Experiments were conducted indoor at five different Reynolds numbers (1447 Re 7237) and three different radiation intensities (430, 573, and 716 W/m2).It is found that the obstacles improve SAH performance. Both the air temperature rise and efficiency increase with inserting obstacles bent at any angle vertically. Unfortunately, the air pressure drop is increasing, too. Obstacles bent vertically at smaller angle (means more straight) give higher air temperature rise and efficiency. However, the optimum angle is found 30o. The air temperature rise and efficiency will be 5.3% lower when the obstacles bent 30oinstead of 0o, but the pressure drop will be 17.2% lower.

Experimental Study and Numerical Analysis of Water Single-Phase Pressure Drop Across a Micro-Pin-Fin Array

2010 ◽  
Author(s):  
Christopher A. Konishi ◽  
Ruey Hwu ◽  
Weilin Qu ◽  
Frank E. Pfefferkorn
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Numerical Analysis ◽  
Single Phase ◽  
Inlet Temperature ◽  
Equivalent Diameter ◽  
Phase Flow ◽  
Single Phase Flow ◽  
Pin Fin ◽  
Pin Fin Array

This study investigates the hydraulic performance of a copper micro-pin-fin array subjected to water liquid single-phase flow conditions. The test section contains an array of 1950 staggered square micro-pin-fins with 200 micron × 200 micron cross-section by 670 micron height. The ratios of longitudinal pitch and transverse pitch to pin-fin equivalent diameter are equal to 2. Seven water inlet temperatures from 22°C to 80°C, and seventeen maximum mass velocities for each inlet temperature, ranging from 181 to 1649 kg/m2s, were tested. The test module was well insulated to maintain adiabatic conditions. Comparison of predictions of eleven existing friction factor correlations with the experimental data show relatively large discrepancies. The experimental study was complemented with a numerical analysis of single-phase flow in the micro-pin-fin array. Numerical results show excellent agreement with experimental data for Reynolds numbers below 700.

Cooling effectiveness of matrix, pin fin array and hybrid structure: A comparative study

2020 ◽  
pp. 095441002096540
Author(s):  
Lianfeng Yang ◽  
Yigang Luan ◽  
Shi Bu ◽  
Haiou Sun ◽  
Franco Magagnato
Keyword(s):  
Heat Transfer ◽  
Comparative Study ◽  
Thermal Performance ◽  
Gas Turbines ◽  
Pressure Loss ◽  
Hybrid Structure ◽  
Hybrid Structures ◽  
Pin Fin ◽  
Pin Fins ◽  
Pin Fin Array

In modern gas turbines, the trailing edge of turbine blades must be cooled by compact heat transfer structures. The basic problems in the design of cooling ducts include enhancing heat transfer, reducing pressure loss and obtaining uniform temperature distribution. The purpose is to improve energy efficiency and guarantee the engine lifespan. In this work, both experiment and numerical simulation are employed to study pressure drop and heat transfer of various kinds of cooling configurations. Pin fin array, matrix and hybrid structures are investigated in a comparative study. Thermochromic liquid crystal technique is applied to obtain heat transfer distribution on the channel surface. The results show that matrix creates much stronger heat transfer than pin fin array with increased pressure loss penalty. Performances of matrix structures are quite different due to the configurations (dense or sparse). Hybrid structures are always worse than the baseline matrix in terms of average thermal performance, due to the higher pressure loss, however, heat transfer can be improved. The performance of hybrid structure depends on the arrangement and diameter of the pin fins. Pin fins in central area provide not only larger pressure loss but also stronger heat transfer than pin fins near the bend region. Cases with larger diameter result in the thermal performance degradation. Compared with sparse matrix, the hybrid structures can compensate for the lower heat transfer enhancement. As for the dense hybrid structures, the average heat transfer capacity can be improved with reasonable pin fin arrangement.

Heat Transfer on Rotating Channel With Various Heights of Pin-Fin

2008 ◽  
Author(s):  
Jun Su Park ◽  
Kyung Min Kim ◽  
Dong Hyun Lee ◽  
Hyung Hee Cho ◽  
Minking K. Chyu
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Transfer Coefficients ◽  
Pin Fin ◽  
Heat Transfer Coefficients ◽  
Naphthalene Sublimation Technique ◽  
Pin Fins ◽  
Naphthalene Sublimation ◽  
Pin Fin Array

Pin-fins have been used to enhance the heat transfer near the trailing edge of a turbine airfoil. Previous pin-fin heat transfer studies focused mainly on the array geometry of pin height-to-diameter equal to unity in a stationary frame. This study experimentally examines the effects of pin height-to-diameter ratio (Hp/Dp) from 2 to 4 and rotation number (Ro) from 0 to 0.2. The tested model used a staggered pin-fin array with an inter-pin spacing of 2.5 times the pin-diameter (S/D = 2.5) in both longitudinal and transverse directions. Detailed heat/mass transfer coefficients were measured using the naphthalene sublimation technique with a heat-mass transfer analogy. The data measured suggest that an increase in Hp/Dp increases the level of array heat/mass transfer. Array averaged Sherwood numbers for Hp/Dp = 3 and Hp/Dp = 4 are approximately 10% and 35% higher than that of Hp/Dp = 2. The effect of rotation induces notable difference in heat/mass transfer between the leading surface and the trailing surface. The heat transfer coefficients change a little although the rotating number increases in the tested range because the pin-fins break the rotation-induced vortices.

scholarly journals Energy analysis of a solar air heater with an absorber plate made of porous material

2021 ◽  
Vol 25 (Spec. issue 2) ◽  
pp. 333-337
Author(s):  
Filiz Ozgen ◽  
Ayse Dayan
Keyword(s):  
Flow Rate ◽  
Energy Analysis ◽  
Inlet Temperature ◽  
Type I ◽  
Solar Air Heater ◽  
Outlet Temperature ◽  
Absorber Plate ◽  
Plate Temperature ◽  
Air Heater ◽  
Plate Type

In this study, the energy analysis of a solar air heater with an absorber plate made of different obstacles was made. Absorber plate of the solar air heater was created with porous steel wool. Three different absorber plates were used for the experimental study. Complex plate (Type I) was used as the first type of absorber plate, less complex plate (Type II) as the second type absorber plate, and flat plate (Type III) the third type absorber plate. On these plates, which are manufactured as three different absorber plates, steel wools are placed in a complex and less complex way. One absorber plate was left empty. In the experiments, the mass-flow rate of the air passing through the air passage channels was taken as 0.05 kg/s and 0.025 kg/s, and the optimum flow rate was found as 0.05 kg/s. In order to make heater efficiency calculations, heater inlet temperature, outlet temperature, absorber plate temperature, ambient temperature and solar radiation values were measured. Efficiency values for different absorber plate were found between 23% and 74%.

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