CFD based thermal efficiency of square shape protruded roughened absorber plate for solar air heater

Author(s):  
Sanjay Sharma ◽  
Ranjit Singh ◽  
Brij Bhushan
2020 ◽  
Vol 8 (2) ◽  
pp. 510-523
Author(s):  
Arrad Ghani Safitra ◽  
Lohdy Diana ◽  
Denny Muhammad Agil ◽  
Julfan Hafiz Fareza ◽  
Nu Rhahida Arini

Solar air heater (SAH) is a renewable energy application for the drying process. SAH has a challenge to produce high performance under uncertain weather. The performance of SAH can be enhanced by providing the absorber plate by adding the fins. This study aims to evaluate the thermal performance of SAH with rectangular fins SAH at low air velocity. This study compares the performance of SAH without fins and SAH with rectangular fins. Two variations of a tilt angle of SAH are 0° and 30° which are observed in this study. The SAH uses a ventilator turbine to suck air into the collector box. The air velocity is 0.01 m/s. The method is experimental. The SAH is tested under real condition from 9 a.m. to 4 p.m. The measurement tools consist of  a pyranometer, an anemometer, a temperature sensor in the inlet section, 3 sensors in the absorber plate, a sensor in the outlet section,  6 temperature sensors in the drying cabinet. The result showed the thermal efficiency of SAH with rectangular fins is 29.67 % higher than SAH without fins at 0˚ tilt of angle at noon. The thermal efficiency of SAH with rectangular fins is 25.26 % higher than  that of without fins at 30˚ tilt of angle at noon.


2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Dhananjay Kumar ◽  
Laljee Prasad

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.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2133 ◽  
Author(s):  
Chii-Dong Ho ◽  
Hsuan Chang ◽  
Zih-Syuan Hong ◽  
Chien-Chang Huang ◽  
Yu-Han Chen

The device performance of recycling double-pass solar air heaters with W-ribs by machining on both sides of the absorber plate is investigated experimentally and theoretically. It is emphasized that in comparing various design configurations, they should be compared for the increase of power consumption suffered by the air passing through the collector under the same air mass flow rate and working dimensions. Compared to those of the single-pass and flat-plate double-pass device, both effects of the external recycle and the artificial W-ribs by machining enhance the collector thermal efficiency in this study. This study proposes an optimal design of the recycling W-ribs double-pass device that is expected to consider the compensation between collector thermal efficiency improvement I W due to the external recycle and the increase of power consumption I P , W owing to pumping the air circulation in the two divided subchannels. The evaluation of a higher ratio of I W to I P , W leads to economic benefits. It has been observed that a relative higher ratio of collector thermal efficiency improvement to the increase of power consumption occurs at recycle ratio R = 0.5. The results indicated the turbulent intensity increment with the artificial W-ribs by machining on both sides of the absorber plate could compensate for the increase of power consumption with the consideration of economic feasibility. The operation of a recycling W-ribs solar air heater with two covers in a double-pass mode offers an inexpensive method of improving the collector thermal efficiency by about 76.65%. The advantage of the present device is evident and provides a feasible design to improve the solar air heater of which the promotion in turbulence effectively raises the convective heat-transfer coefficient. The collector thermal efficiency enhancement of the double-pass operation is much higher than that in the smooth plate under different recycle ratios and mass flow rates.


2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
B. K. Maheshwari ◽  
Rajendra Karwa ◽  
S. K. Gharai

The paper presents a detailed mathematical model for performance prediction of a smooth duct solar air heater validated against the experimental results. Experimental study on a solar air heater having absorber plate with half-perforated baffles on the air flow side shows thermal efficiency enhancement of 28%–45% over that of the smooth duct solar air heater, which is attributed to the heat transfer enhancement (of the order of 180%–235%) due to the perforated baffles attached to the absorber plate and reduction in the mean temperature of the absorber plate by 20°C–25°C as compared to the temperature of absorber plate of smooth duct air heater. Using the mathematical model, the performance plot for the baffled duct air heater has been presented, and the effect of the variation of ambient parameters on the predicted thermal efficiency has been studied.


2017 ◽  
Vol 5 (4) ◽  
pp. 320-333
Author(s):  
Gade Bhavani Shankar ◽  
P.S. Kishore

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.


2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Satyender Singh ◽  
Prashant Dhiman

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.


Author(s):  
Vijayakumar Rajendran ◽  
Harichandran Ramasubbu ◽  
Karthick Alagar ◽  
Vignesh Kumar Ramalingam

An experimental study has been carried out to enhance a solar air heater’s performance by integrating artificial roughness through baffles on the absorber plate. In this paper, the thermal and energy matrices analysis of a Solar Air Heater (SAH) roughened with V up perforated baffles have been investigated. The effect of various mass flow rates on the SAH was analyzed with and without baffles. Experimental outputs like outlet air temperature, useful energy (heat) gain and thermal efficiency were evaluated to confirm the performance improvement. The baffled absorber plate SAH was found to give the maximum thermal efficiency and useful energy gain of 89.3% and 1321.37 W at a mass flow rate of 0.0346 kg/s, 13% and 12% higher than SAH without baffle. This result showed that the V up-shaped ribs in flow arrangement provide better thermal performance than smooth plate SAH for the parameter investigated. Energy matrices analysis and carbon dioxide mitigation of the SAH system were also analyzed.


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