Transient Considerations of Flat-Plate Solar Collectors

1974 ◽  
Vol 96 (2) ◽  
pp. 109-113 ◽  
Author(s):  
S. A. Klein ◽  
J. A. Duffie ◽  
W. A. Beckman
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Meteorological Data ◽  
Weather Conditions ◽  
Operating Conditions ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Thermal Capacitance ◽  
Flat Plate Solar Collector ◽  
Capacitance Effects

The effects of thermal capacitance in the modeling of the performance of a flat plate solar collector have often been neglected because of the computation involved. But because the solar collector is inherently exposed to continuously variable weather conditions, capacitance effects may be significant. To investigate these effects, three different models of flat-plate collectors have been investigated. The first, a quasi-steady-state model, simulates the performance of a collector of zero capacitance. The second model accounts for capacitance effects by assuming that a single value of thermal capacitance can be determined for the collector as a unit. The third model divides the collector into many isothermal segments, or nodes. For all three models the heat transfer coefficients are calculated as a function of operating conditions. The results show that, when hourly meteorological data are used, the zero-capacitance model is adequate.

Numerical Investigation of the Effects of Environmental Parameters and Geometry on Energy Absorption for an Open-type Water-cooled Flat-plate Solar Collector

2000 ◽  
Vol 122 (2) ◽  
pp. 56-62 ◽  
Author(s):  
B. Song ◽  
H. Inaba ◽  
A. Horibe
Keyword(s):  
Heat Flux ◽  
Flat Plate ◽  
Energy Absorption ◽  
Tilt Angle ◽  
Solar Collector ◽  
Water Film ◽  
Operating Conditions ◽  
Open Type ◽  
Type Water ◽  
Flat Plate Solar Collector

A two-dimensional mathematical model was developed for predicting the performance of an open-type water-cooled flat-plate solar collector, and solved numerically through an implicit finite difference method. The effects of various environmental and geometric conditions on energy absorption for the collector were investigated. The results predict that there is an optimum length and tilt angle for the absorbing plate for which the collector could obtain the highest solar energy absorptance. The latent heat flux of water evaporation can be 3 to 15 times larger than the sensible heat flux under normal operating conditions. The wind speed and the inlet water temperature have a large influence on the energy absorption of the collector. The effects of the solar incident flux, the atmospheric humidity and temperature, the absorbing plate tilt angle and length, and the water film thickness on the temperature rise of the water film and/or the absorptance of the collector are clarified. The open-type flat-plate collector is suitable to operate at lower inlet water temperatures and in regions where the local latitude is in the range of 20°N-40°N, and the weather is humid and hot with low winds. [S0199-6231(00)00202-1]

scholarly journals Experimental Evaluation of a Flat Plate Solar Collector Under Hail City Climate

2018 ◽  
Vol 8 (2) ◽  
pp. 2750-2754
Author(s):  
N. Ben Khedher
Keyword(s):  
Flat Plate ◽  
Flow Rate ◽  
Solar Collector ◽  
Weather Conditions ◽  
Water Heater ◽  
Optimum Flow Rate ◽  
Water Heaters ◽  
Flat Plate Solar Collector ◽  
Flat Plate Collector ◽  
Solar Water Heaters

Flat plate solar water heaters are widely used for water heating in low-temperature residential applications. In this paper the thermal performance of a solar flat plate water heater under Hail weather conditions (latitude 27°52΄N longitude ‎41°69΄E) was experimentally investigated. Fluid was circulated through the imbedded copper tubes in the flat plate collector and inlet and outlet temperatures of the fluid were noted at five minute intervals. The experimental-time was between 9:00AM-15:00PM. A study was carried out experimentally to present the efficiency curves of a flat plate solar collector at different flow rates. ASHRAE standard 93-2003 was followed for calculation of instantaneous efficiency of solar collector. Result shows that the flow rate of the circulating fluid highly influence the thermal efficiency of the solar collector. Optimum flow rate of 2.5L/min leads to maximum collector efficiency.

Effect of Adiabatic Co-Planar Extension Surfaces on Wind-Related Solar-Collector Heat Transfer Coefficients

1981 ◽  
Vol 103 (2) ◽  
pp. 268-271 ◽  
Author(s):  
E. M. Sparrow ◽  
S. C. Lau
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Solar Collector ◽  
Leading Edge ◽  
Transfer Coefficients ◽  
Trailing Edge ◽  
Heat Transfer Coefficients ◽  
Planar Extension ◽  
Flat Plate Solar Collector

The heat transfer response to framing the thermally active cover surface of a flat plate solar collector with adiabatic co-planar extension surfaces has been investigated by wind tunnel experiments. Various framing patterns were employed (leading edge and/or trailing edge and/or side edge framing), along with frames of different width. The experiments were performed for various angles of inclination of the plate surface relative to the oncoming airstream and for a range of Reynolds numbers. It was found that the wind-related heat transfer coefficients can be substantially lower when the collector is framed than when it is unframed. An estimate of the possible reduction of the average heat transfer coefficient can be obtained from the equation h/h* = (Lc/Lf)1/2, where h and h* respectively denote the coefficients in the presence and in the absence of the frame. The quantity Lc is a dimension that is characteristic of the thermally active area of the cover surface, while Lf is a characteristic dimension of the outer edges of the frame. With respect to the reduction of the heat transfer coefficient, framing along the side edges appears to be more beneficial than framing along the leading and trailing edges, as is framing along the trailing edge compared with framing along the leading edge.

The Effect of Local Meteorological Conditions on the Optimal Tilt Angle of a Solar Energy Collector—A Case Study in Poland

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Ryszard Myhan ◽  
Jacek Bieranowski ◽  
Zbigniew Szwejkowski ◽  
Eliza Sitnik
Keyword(s):  
Solar Radiation ◽  
Flat Plate ◽  
Tilt Angle ◽  
Solar Collector ◽  
Meteorological Data ◽  
Active Surface ◽  
Meteorological Conditions ◽  
Energy Output ◽  
Flat Plate Solar Collector

This study compares the potential annual energy absorption of a flat-plate solar collector at different tilt angles in Poland. Optimal tilt angles were tested in three variants: over the course of the year, in fall/winter and in spring/summer. The results were compared with automatically tracked collectors where the active surface is perpendicular to the angle at which solar radiation reaches the collector. The results were simulated based on the meteorological data. A comparison of the energy outputs of solar collectors in optimization variants 1, 2, and 3 indicates that variant 1 produces the highest energy output.

scholarly journals Performance Evaluation of Flat Plate and Vacuum Tube Solar Collectors by Applying a MWCNT/Fe3O4 Binary Nanofluid

Energies ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1715
Author(s):  
Minjung Lee ◽  
Yunchan Shin ◽  
Honghyun Cho
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
High Performance ◽  
Operating Conditions ◽  
Working Fluid ◽  
Efficiency Improvement ◽  
Solar Collectors ◽  
Vacuum Tube ◽  
Flat Plate Solar Collector ◽  
Wide Operating

This study experimentally investigated the performance characteristics of water and MWCNT/Fe3O4 binary nanofluid as a working fluid in a flat plate and vacuum tube solar collectors. As a result, the highest efficiency was 80.3% when 0.005 vol.% MWCNT/0.01 vol.% Fe3O4 binary nanofluid was applied to the flat plate solar collector, which was a 17.6% increase in efficiency, compared to that when water was used. In the case of the vacuum tube solar collector, the highest efficiency was 79.8%, which was 24.9% higher than when water was applied. Besides, when the mass flux of MWCNT/Fe3O4 binary nanofluid was changed from 420 to 598 kg/s·m2, the maximum efficiencies of the flat plate and vacuum tube solar collectors were increased by 7.8% and 8.3%, respectively. When the MWCNT/Fe3O4 binary nanofluid was applied to the vacuum tube solar collector, the efficiency improvement was much more significant, and the high performance could be maintained for wide operating conditions, compared with the flat plate solar collector.

scholarly journals The Effect of Coupling Flat Plate Collectors with Basin-Solar Stills

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
S. A Srbet ◽  
T. M Jaballa ◽  
E. I Dekam
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Complex Function ◽  
Operating Conditions ◽  
Water Production ◽  
Operational Conditions ◽  
Site Characteristics ◽  
Single Effect ◽  
Flat Plate Solar Collector ◽  
Operational Modes

Two identical single - effect of single basin solar stills were designed, fabricated, tested and evaluated. One was operated alone while the other was coupled to a flat plate solar collector. Both were installed at some site in Tripoli, Libya at 32" 48' 51' N and 13’’26' I7' E. They were south oriented with a tilt angle of 23“. Measurements of various parameters were taken in August 2009 at each hour for several days under different operating conditions. Two operational modes were considered. The tests were conducted using seawater of 35,000 ppm. The depth of water in the basin was kept fixed at 60 mm. Fresh water production of the coupled still was measured to be 6.6 L/day which is higher than that of the single still by 55.84%. The maximum daily efficiency was calculated to be 14.48% for the single still while it was only 24.18% for the coupled still. The still thermal performance was found to have a complex function of geometry, construction, operational conditions, site characteristics and layout details.

scholarly journals The Effect of Coupling Flat Plate Collectors with Basin-Solar Stills (reprinted)

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
S. A Srbet ◽  
T. M Jaballa ◽  
E. I Dekam
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Complex Function ◽  
Operating Conditions ◽  
Water Production ◽  
Operational Conditions ◽  
Site Characteristics ◽  
Single Effect ◽  
Flat Plate Solar Collector ◽  
Operational Modes

Two identical single - effect of single basin solar stills are designed, fabricated, tested, and evaluated. One is operated alone while the other is coupled to a flat plate solar collector. Both are installed at the same site in Tripoli, Libya, at 32º 48´ 51?N and 13º 26´ 17?E. They are oriented due to south with a tilt angle of 23°. Measurements of various parameters are taken in August 2009 at each hour for several days under different operating conditions. Two operational modes are considered. The tests were conducted using seawater of 35,000 ppm. The depth of water in the basin is kept fixed at 60 mm. Fresh water production of the coupled still is measured to be 6.6 L/day which is higher than that of the single still by 55.84%. The maximum daily efficiency is calculated to be 14.48% for the single still while it is only 24.18% for the coupled still. The still thermal performance is found to have a complex function of geometry, construction, operational conditions, site characteristics and layout details.

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