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Technical Brief

View Factors to Grounds of Photovoltaic Collectors

[+] Author and Article Information
J. Appelbaum

School of Electrical Engineering,
Tel Aviv University,
Tel Aviv 69978, Israel
e-mail: appel@eng.tau.ac.il

Contributed by the Solar Energy Division of ASME for publication in the JOURNAL OF SOLAR ENERGY ENGINEERING: INCLUDING WIND ENERGY AND BUILDING ENERGY CONSERVATION. Manuscript received November 8, 2015; final manuscript received July 4, 2016; published online September 2, 2016. Assoc. Editor: Philippe Blanc.

J. Sol. Energy Eng 138(6), 064501 (Sep 02, 2016) (6 pages) Paper No: SOL-15-1371; doi: 10.1115/1.4034316 History: Received November 08, 2015; Revised July 04, 2016

Ground reflected radiation is one component of the global radiation on photovoltaic collectors in a solar field. This component depends on the view factor of the collector to ground, hence depends on the relative position of the collectors to each other. General analytical expressions and numerical values for the view factor to the ground were developed between flat-plate collectors positioned in a general configuration. Based on the general expression, the view factors to ground for particular collector configurations were derived. For deployment of photovoltaic collectors in multiple rows with common inclination angles, the view factor to ground is rather small, and hence, the reflected radiation from the ground on the collectors may be neglected compared to the direct beam and the diffuse components. However, in some cases the reflected radiation from the ground may constitute an appreciable amount as in snowy area. Bifacial photovoltaic (PV) panels can absorb solar radiation by both the front and the rear sides and are usually deployed vertically. In this case the reflected radiation from the ground on the panels may be appreciable depending on the ground albedo. The mathematical expressions of the different view factors may be used by the solar field designer to estimate the amount of reflected radiation from the ground reaching the collectors for different configurations of solar PV plants.

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References

Energy Technology and Engineering, 2014, “ Bifacial PV Modules: Can They Move Beyond BIPV Applications?,” Energy Engineer Blogspot.
Brennan, M. P. , Abramase, A. L. , Andrews, R. W. , and Pearce, J. M. , 2014, “ Effects of Spectral Albedo on Solar Photovoltaic Devices,” Sol. Energy Mater. Sol. Cells, 20, pp. 111–116. [CrossRef]
McEvoy, A. , Markvart, T. , and Castaner, L. , 2012, Practical Handbook of Photovoltaics Fundamentals and Applications, 2nd ed., Academic Press, Waltham, MA.
Loutzenhiser, P. G. , Manz, H. , Felsmsnn, C. , Strachan, P. A. , Frank, T. , and Maxwell, G. M. , 2007, “ Empirical Validation of Models to Compute Solar Irradiance on Inclined Surfaces for Building Energy Simulation,” Sol. Energy, 81(2), pp. 254–267. [CrossRef]
Jones, R. E., Jr. , and Burkhart, J. F. , 1981, “ Shading Effect of Collector Row Tilt Toward the Equator,” Sol. Energy, 26(6), pp. 563–565. [CrossRef]
Bany, J. , and Appelbaum, J. , 1987, “ The Effect of Shading on the Design of a Field of Solar Collectors,” Sol. Cells, 20(3), pp. 201–228. [CrossRef]
Maor, T. , and Appelbaum, J. , 2012, “ View Factors of Photovoltaic Collector Systems,” Sol. Energy, 86(6), pp. 1701–1708. [CrossRef]
Appelbaum, J. , and Aronescu, A. , 2016, “ View Factors of Photovoltaic Collectors on Roof Tops,” J. Renewable Sustainable Energy, 8(2), p. 025302. [CrossRef]
Duffie, J. A. , and Beckman, W. A. , 1991, Solar Engineering of Thermal Processes, Wiley, New York.
Hottel, H. C. , and Sarofim, A. F. , 1967, Radiative Transfer, McGraw-Hill, New York, pp. 31–39.
Appelbaum, J. , 2015, “ Bifacial Photovoltaic Panels Field,” Renewable Energy, 85, pp. 338–343. [CrossRef]

Figures

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Fig. 1

Deployment of PV collectors on a horizontal roof

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Fig. 2

Deployment of PV collectors on an inclined roof

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Fig. 3

Deployment of PV collectors on a saw-tooth roof

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Fig. 4

View factor to ground

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Fig. 5

Adjacent collectors A and H on an inclined plane—a general case

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Fig. 6

Collector A with angle μ and second collector H with angle β raised by B

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Fig. 7

Collectors H with inclination angle β on an inclined plane

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Fig. 8

Variation of view factor to ground with raising the collector—front side, H=2.0 m and D=1.0 m

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Fig. 9

Variation of view factor to ground with raising the collector—rear side, H=2.0 m and  D=1.0 m

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Fig. 10

Collectors H with inclination β on a horizontal plane

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Fig. 11

Variation of view factors to ground with inclination angle β —front side, H=2.0 m and  D=1.0 m

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Fig. 12

Variation of view factors to ground with inclination angle β —rear side, H=2.0 m and  D=1.0 m

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Fig. 13

Vertical wall A and collector H raised by B on inclined plane ε

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Fig. 14

Vertical wall A and inclined collector H with inclination β, on a horizontal plane

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Fig. 15

Variation of view factors to ground with distance D between the collector and wall—front side, H=2.0 m, β=30 deg, and β=50 deg

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Fig. 16

Vertical collectors H on a horizontal plane

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Fig. 17

Variation of the view factor to ground with the distance between the vertical collectors, H=2.0 m

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