Experimental Investigation on Thermal Performance in Three-Sided Solar Air Heaters Having an Alignment of Multi-v and Transverse Wire Roughness on the Absorber Plate

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Dhananjay Kumar ◽  
Laljee Prasad
Keyword(s):  
Thermal Performance ◽  
Thermal Efficiency ◽  
Roughness Height ◽  
Space Heating ◽  
Solar Air Heater ◽  
Artificial Roughness ◽  
Absorber Plate ◽  
Air Heater ◽  
Relative Roughness ◽  
Operational Constraints

Abstract The use of artificial roughness is an efficient and commercial way to appreciate the thermal performance from the collector to the air in solar air heater ducts, for numerous applications such as space-heating, crop-drying, and seasoning of timber industrial purpose. In this paper, the tentative inquiry on thermal enactment using new-fangled of three-sided roughened quadrilateral duct solar air heater having an alignment of multiple-v and transverse wire is performed and compared the outcomes with smooth duct air heater under similar operational circumstances. The modification of an arrangement and operational constraints is inspected within the restrictions, the moral of four-sided duct aspect ratio (W/H) = 8, the Reynolds number occupied from 3000 to 12,000, fraction of pitch to roughness height, P/e in the range of 10–25; ratio of roughness height to hydraulic diameter, e/D in the range of 0.018–0.042; at flow attack angle, α = 60 deg for constant moral of relative roughness width, (W/w) = 6. The augmentation on thermal efficiency in three-sided rugged duct is found to be 23–86% when compared to smooth duct, and the maximum thermal efficiency can occur at P/e = 10 and e/D = 0.042. The enhancement in air temperature flowing under three-sided roughened duct is found to be 49.27% more than that of a smooth duct. The instant innovative form of three-sided roughened solar air warmer would be preferable to those of a smooth solar air heater with respect to heat assignment.

scholarly journals THERMOHYDRAULIC PERFORMANCE OF AN EQUILATERAL TRIANGULAR DUCT WITH ARTIFICIAL ROUGHNESS USED IN SOLAR AIR HEATER

2013 ◽  
pp. 46-51
Author(s):  
GAURAV BHARADWAJ ◽  
VARUN VARUN ◽  
AVDHESH SHARMA
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Angle Of Attack ◽  
Roughness Height ◽  
Solar Air Heater ◽  
Artificial Roughness ◽  
Absorber Plate ◽  
Air Heater ◽  
Relative Roughness

The thermohydraulic performance of artificially roughened equilateral triangular solar air heater duct has been investigated and the comparision of the same has been presented with that of a conventional smooth solar air heater duct. The range of relative roughness height (e/Dh) is from 0.021 to 0.043, value of angle of attack (α) and relative roughness pitch (p/e) has been 30° and 8 respectively. The range of Reynolds number is from 5600 to 28000 and aspect ratio of the duct is 1.15. It has been found that the thermohydraulic performance of artificially roughened triangular solar air heater duct is always more than that of the smooth absorber plate in the range of Reynolds number investigated.

scholarly journals Modeling and Simulation of Turbulent Flows through a Solar Air Heater Having Square-Sectioned Transverse Rib Roughness on the Absorber Plate

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Anil Singh Yadav ◽  
J. L. Bhagoria
Keyword(s):  
Heat Transfer ◽  
Turbulent Flows ◽  
Convective Heat Transfer Coefficient ◽  
Performance Parameter ◽  
Roughness Height ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Air Heater ◽  
Relative Roughness ◽  
Flow Through

Solar air heater is a type of heat exchanger which transforms solar radiation into heat energy. The thermal performance of conventional solar air heater has been found to be poor because of the low convective heat transfer coefficient from the absorber plate to the air. Use of artificial roughness on a surface is an effective technique to enhance the rate of heat transfer. A CFD-based investigation of turbulent flow through a solar air heater roughened with square-sectioned transverse rib roughness has been performed. Three different values of rib-pitch (P) and rib-height (e) have been taken such that the relative roughness pitch (P/e=14.29) remains constant. The relative roughness height,e/D, varies from 0.021 to 0.06, and the Reynolds number, Re, varies from 3800 to 18,000. The results predicted by CFD show that the average heat transfer, average flow friction, and thermohydraulic performance parameter are strongly dependent on the relative roughness height. A maximum value of thermohydraulic performance parameter has been found to be 1.8 for the range of parameters investigated. Comparisons with previously published work have been performed and found to be in excellent agreement.

scholarly journals Thermal Performance of Solar Air Heater Having Absorber Plate with V-Down Discrete Rib Roughness for Space-Heating Applications

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Rajendra Karwa ◽  
V. Srivastava
Keyword(s):  
Ambient Temperature ◽  
Thermal Performance ◽  
Air Flow ◽  
Winter Season ◽  
Space Heating ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Fixed Temperature ◽  
Air Heater ◽  
Heated Air

The paper presents results of thermal performance analysis of a solar air heater with v-down discrete rib roughness on the air flow side of the absorber plate, which supplies heated air for space heating applications. The air heater operates in a closed loop mode with inlet air at a fixed temperature of 295 K from the conditional space. The ambient temperature varied from 278 K to 288 K corresponding to the winter season of Western Rajasthan, India. The results of the analysis are presented in the form of performance plots, which can be utilized by a designer for calculating desired air flow rate at different ambient temperature and solar insolation values.

scholarly journals PERFORMANCE ANALYSIS OF A CONVENTIONAL AIR HEATER

2017 ◽  
Vol 5 (4) ◽  
pp. 320-333
Author(s):  
Gade Bhavani Shankar ◽  
P.S. Kishore
Keyword(s):  
Performance Analysis ◽  
Solar Energy ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Heating System ◽  
Climatic Conditions ◽  
Solar Air Heater ◽  
Ambient Conditions ◽  
Absorber Plate ◽  
Air Heater

Solar energy constitutes one of the main alternatives for facing the energy problems of the future. Solar air heaters are used for applications at low and moderate temperatures. Such as crop drying, timber seasoning, space heating, and drying agriculture products. Artificial geometry applied on the absorber plate is the very efficient method to improve thermal performance of solar air heaters. The thermal efficiency of solar air heaters is generally poor due to low heat transfer coefficient between the absorber plate and air flowing in the collector. Thermal performance of the conventional solar air heater was studied under varying solar and ambient conditions in different months. At day time the solar heating system stored the thermal solar energy as sensible and latent heat.  A parametric study was done for 10 months for the climatic conditions of Visakhapatnam. The effect of change in the tilt angle, length and breadth of a collector and mass flow rate on the temperature of collector has been studied. The length of the collector is 2.1m and width of the collector is 1.1 m. the performance analysis of system shows potential of improving the thermal efficiency range is 31% to 47% .From the obtained results, graphs are drawn to assess the performance analysis of a conventional air heater.

Thermal Performance Analysis of a Rectangular Longitudinal Finned Solar Air Heater With Semicircular Absorber Plate

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Satyender Singh ◽  
Prashant Dhiman
Keyword(s):  
Thermal Performance ◽  
Numerical Solutions ◽  
Solar Air Heater ◽  
Duct Flow ◽  
Balance Equations ◽  
Absorber Plate ◽  
Ansys Fluent ◽  
Air Heater ◽  
Glass Cover ◽  
Good Agreement

Thermal performance of a single-pass single-glass cover solar air heater consisting of semicircular absorber plate finned with rectangular longitudinal fins is investigated. The analysis is carried out for different hydraulic diameters, which were obtained by varying the diameter of the duct from 0.3–0.5 m. One to five numbers of fins are considered. Reynolds number ranges from 1600–4300. Analytical solutions for energy balance equations of different elements and duct flow of the solar air heater are presented; results are compared with finite-volume methodology based numerical solutions obtained from ansys fluent commercial software, and a fairly good agreement is achieved. Moreover, analysis is extended to check the effect of double-glass cover and the recycle of the exiting air. Results revealed that the use of double-glass cover and recycle operation improves the thermal performance of solar air heater.

Impact of relative roughness height on the materialistic thermohydraulic performance of the multiple V-ribbed solar air heater

2020 ◽  
Vol 26 ◽  
pp. 1845-1849
Author(s):  
Gagan Bansal ◽  
Chandra Kishore ◽  
Vaishally Dogra ◽  
Amit Bansal ◽  
Rahul Keshari
Keyword(s):  
Roughness Height ◽  
Solar Air Heater ◽  
Air Heater ◽  
Relative Roughness

scholarly journals Effect of rib roughness pitch on thermal and thermo-hydraulic performance of a solar air heater roughened artificially with arc rib having gap

2016 ◽  
Vol 8 (1) ◽  
pp. 251-256
Author(s):  
V. S. Hans ◽  
R. S. Gill ◽  
Rupinderpal Singh
Keyword(s):  
Hydraulic Performance ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Degree Relative ◽  
Number Range ◽  
Air Heater ◽  
Relative Roughness ◽  
Flow Reynolds Number ◽  
Gap Width ◽  
Rib Roughened

This experimental study on a solar air heater having absorber plate roughened artificially by providing roughness in the form of arc ribs having gap was carried out in the Department of Mechanical Engineering, Punjab Agricultural University, Ludhiana, India to study the effect of relative roughness pitch on thermal and thermohydraulic performance as well as to compare the performance of arc rib with gap roughened solar air heater with that of continuous arc rib roughened solar air heater. The roughness geometry parameters included relative roughness height of 0.043, angle of attack of 30 degree, relative gap position of 0.80, gap-width equal to the width of the rib and five values of relative roughness pitch ranging from 4 to 12 for flow Reynolds number range of 2000 to 16,000. The Nusselt number and friction factor were found to be more for relative roughness pitch value of 10 as compared to other values of relative roughness pitch. Thermo-hydraulic performance of solar air heaters roughened by arc with gap and continuous arc roughness geometries were found to be 1.91 times and 1.78 times respectively as compared to that of solar air heater having smooth absorber plate due to generation of turbulence in laminar sublayer region. However, improvement in thermo-hydraulic performance of solar air heater roughened by arc with gap geometry over continuous arc rib roughened solar air heater was attributed to generation of a region of turbulence on downstream side of the gap.

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