Photothermal conversion in a solar collector with tilted walls (original) (raw)
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Solar photovoltaic/thermal air collector with mirrors for optimal tilts
International Journal of Electrical and Computer Engineering (IJECE), 2022
This work is the result of a study of a photovoltaic/thermal air collector that concentrates solar radiation using two mobile mirrors to enhance electrical and thermal energy. The study is made for the site of Tetouan (Morocco) (longitude=-5°, latitude=35.25°) for a daily variation during typical days in May, June, September, and December, days considered as clear sky. To prove the effectiveness of the mirrors on the production of both electrical and thermal energy by the collector, we compared their electrical and thermal efficiency in two cases, without and with mirrors at the optimal positions. We validate the obtained simulation results by comparing them to the results from experimental studies published in the literature, for which a strong agreement was obtained. The model estimates the solar energy received by the hybrid collector during the day, to optimize the performance of the fixed collector, we have searched for the values of the optimal daily tilt angles of the two mir...
Investigations of Air Solar Collector Efficiency
2009
In 2005 in the research laboratory equipment for experimental research into the materials of solar air collectors was built for research purposes. The construction of the equipment allows simultaneous comparative studies of materials and types. The experimental data are metered and recorded in the electronic equipment REG. Covered material polystyrol with absorbers steel-tinplate and black colored wood was researched in relation to others and location at different places of absorber. The ambient air worming degree at a stationary and sun following air collector with an equal coating surface and absorbers is compared. The air heating degreeT in the solar collector is dependent on solar radiation I, air velocity v, type and place of absorbers. In the experimental equipment, with dimensions 10x50x100 cm , the air got hot toT = 6 °C in stationary positions with steel-thin plate and sun following position it rose toT = 10 °C at the velocity v = 0.55 m/s. On the supposition that the heati...
Thermal Analysis of a Pentagonal Solar Air Collector
The Journal of The University of Duhok
In this paper, a pentagonal shaped Solar Air Collector (SAC) is proposed. The pentagon design is used to improve the incident radiation angle. The SAC is tested in University of Duhok campus, Kurdistan Region, Iraq in a stand facing south. The absorber made from the sandwich steel panel plate with an area of 0.9*1.5 m 2 and thickness of 0.4 mm. The collector is covered with a Plexiglas of thickness 5 mm. The effect of the air flow channel on the collector efficiency is studied. Experimental studies are carried out for different tilt angles to show the improvement in the collector performance. The collector is tested for four sunny days in the same atmospheric conditions in December as the worst month. The results demonstrate that the optimum tilt angle of the day will substantially enhance the thermal efficiency comparing to latitude tilt angle. In addition, the proposed SAC with closed channel and open channel shows different performance during the day time.
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2012
The objective is to create and explore the easy-folding, disrupting, easily portable air heating solar collectors, which can be inflated and disassembled as many times as needed. The solar collector has to be constructively simple and cheap as well as simple and easy to transport. That could be an inflatable air heating solar collector. The inflatable base could be a good insulator on the one hand and absorbent on the other hand. We need to find out the air-heating collector efficiency. The study results confirm that the manufactured solar collector is sufficiently effective and easy to produce with small financial contributions. The average ambient air temperature increase in the experiments is 10.2 oC and max increase is up to 16 oC. This collector gives good correlation with the air heating degree and radiation ( r = 0.93) and the efficiency coefficient of this collector is � = 0.63. Comparing the efficiency of the collector manufactured with another coating and the absorbent mat...
Solar Energy, 2018
The research had the following objectives: to assess the efficiency of a collector and the reliability of the applied parameters such as the outlet air velocity, temperature increase depending on the intensity of solar irradiance, the influence of ambient temperature on the collector's efficiency and heat loss. The solar-air collector (1180 mm × 610 mm × 77 mm (height, width, depth)) was installed vertically on a South-faced wall and exposed to solar irradiance. The following parameters were measured in the course of study: intensity of solar irradiance falling on a vertical surface (the collector was installed in a vertical position according with the producer design), temperature and velocity of air flowing into the collector as well as the temperature and velocity of air flowing out of the device. The study indicates that the collector worked efficiently at an irradiance value of just 100 W•m −2 and heated up the flowing air by about 5°C. This temperature increased together with increasing irradiance and reached the value of 20°C at the irradiance value of 800 W•m −2. The analysis of the collector's efficiency showed that during its work (proper temperature and irradiance) the efficiency remained at a satisfactory level from 42 to 46%.
Thermal performance of a cylindrical solar collector
Energy Conversion and Management, 1991
A new, cylindrical-type solar collector is designed, built and tested. The absorber is a steel cylinder, 580 mm dia, in which another cylinder, 510 mm dia, is placed. An annular gap, 35 mm wide, is thereby formed betwen the two cylinders, and the gap is filled with water. The outside cylinder is enclosed by plastic film glazing, and the ends of the cylinder are insulated. The collector's cylindrical axis is tilted 45 ' D to the horizontal such that the vertical plane including this axis is oriented due south. The direct solar radiation falling on the collector is thereby interrupted by the same projected area of the collector without the need for tracking. Water in the annular gap is heated and circulated via the thermosyphonic driving force. The instantaneous efficiency curve is experimentally obtained. The maximum efficiency obtained is 85%.
Different Material Investigations in Air-Heating Flat-Plate Solar Collector
2011
The aim of the investigations was to compare different absorber material efficiency and also efficiency of isolated and non isolated collectors. The 0.1x0.5x1.0 meters long experimental solar collector was constructed for investigations and different types of absorber materials were made. We analyzed the manifold length, sun radiation effect on the degree of air heating. ASHARE used standard 93-2003 is calculated for each type of solar collector and absorber effectiveness. We determined the influence of sun radiation to the air heating degree for these types of absorbers. The experimental data were measured and recorded in the electronic equipment REG. The collector covered material was a polystyrol plate and different absorbers. We compared isolated and non isolated collectors to prove that the isolated collector is more effective. The isolated collector was made by the collector surfaces faced with cellular plastic 2 cm plates. Our task was to calculate the air heating solar colle...
International Journal of Ambient Energy, 2011
This article presents the results of the first experimental investigation of the performance of solar air flat plate collector at Biskra (latitude 34 48 0 N and longitude 5 44 0 E), Algeria. The thermal efficiency between absorber plate and air in flat plate solar collector has been enhanced by introducing obstacle rows in the dynamic air vein of the collector. For this objective, a flat plate solar collector, of 1.73 m 2 area and 25 mm air gap, has been designed and constructed. These obstacles formed with two parts: first part is perpendicular to fluid flow and the second part is inclined, they are mounted in a staggered pattern, oriented perpendicular to the fluid flow and soldered to the back plate. The solar air heater was mounted on a stand facing south at inclination angle, and it was tested under the environmental conditions. Moreover, a theoretical approach is employed for determination of the thermal performances of this collector where the temperatures of all components of the collector and outlet air are predicted. Comparisons among the experimental and theoretical results considered are reported.