A general expression for the shadow geometry for fixed mode horizontal, step-like structure and inclined solar fields

Alsadi, Samer; Nassar, Yasser F.

doi:10.1016/j.solener.2019.01.090

Cited by 34 publications

(16 citation statements)

References 14 publications

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“…The effect of row distance shading on the output of PV modules is reported in [7]. References [8,9] follow the above studies and include step-like structures and sloped grounds facing south. The study in [8] is an extension to [3] and deals with the analytical formulation of shading on PV collectors deployed on horizontal and step-like collectors (equivalent to sloped surfaces) facing south.…”

Section: Introductionmentioning

confidence: 99%

Shading and Masking of PV Collectors on Horizontal and Sloped Planes Facing South and North—A Comparative Study

2021

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With the increase in PV system installations, the available free land and rooftops for these systems may become scarcer, and therefore sloped fields facing the north may be utilized for that purpose. In deployments of PV collectors in multiple rows, either on horizontal or sloped planes, the second and subsequent rows are subject to two effects: shading and masking. Both effects reduce the electric energy generated by the PV systems. Multiple rows of collectors are deployed on horizontal planes and on sloped planes facing south, and literature on the topic has been published. No literature deals analytically with deployments of PV fields on north-facing slopes in the northern hemisphere, to the best of our knowledge. The present study develops explicit analytical expressions for the shadow height and length cast on a collector row by a row in front in multiple-row PV systems installed on slopes facing north. In addition, analytical expressions are developed for row spacing and sky view factors, altogether leading consequently to the determination of shading and masking losses. Having the developed expressions, a comparison was made between PV deployments on north-facing sloped planes to PV deployments on horizontal and south-facing slopes regarding shading and masking losses. The main finding is that the percentage of masking losses (diffuse radiation) may exceed the percentage of shading losses (beam radiation) in PV fields. At the local site 32∘ N, collector inclination angle β=25∘ and sloped-plane ε=10∘, for example, the percentage of masking losses for a horizontal plane is 6.90%; for a sloped plane facing south, the losses are 5.39%, and for a sloped plane facing north, the losses are 6.86%. In comparison to the masking losses, the percentage of shading losses for the horizontal plane is 0.83%; for the sloped plane facing south, the losses are 0.42%, and for the sloped plane facing north, the losses are 1.37%.

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Section: Introductionmentioning

confidence: 99%

Shading and Masking of PV Collectors on Horizontal and Sloped Planes Facing South and North—A Comparative Study

2021

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“…Shading causes uneven distribution of the incident solar radiation on the PV modules, resulting in the formation of steps across the I-V characteristics. Articles that include analytical expressions for shading on PV collectors in solar fields are mentioned in [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Shadow analysis and its effect on solar PV systems for flat-plate collectors was started early by [3] and followed by [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…References [10][11][12][13][14] also calculate the shading losses. With the wide broadening of PV plants across the world, authors recently returned to deal with the shading losses of PV systems [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

“…A method to calculate the minimum distance between the rows to avoid the effect of shadings is developed in [16]. In [17] the coordinates of the shadow on solar collectors are determined for horizontal, step-like, and inclined solar fields. The calculation of row spacing was developed in [18] using a vector analysis method for PV systems on horizontal and non-horizontal planes, and then comparing this method with a ray tracing shadow Appl.…”

Section: Introductionmentioning

confidence: 99%

“…The distance from a building object to the PV array was calculated in [19], based on the Solo Pro software simulation tool; however, no mathematical expressions for the shading were specified. The references [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] deal with analytical expressions for the spacing between rows for PV systems deployed on the ground, the exception is reference [19].…”

Section: Introductionmentioning

confidence: 99%

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Shading on Photovoltaic Collectors on Rooftops

Aronescu

Appelbaum

2020

Applied Sciences

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Rooftop photovoltaic (PV) systems in urban environments play an important role in solar electric energy generation. Shading on PV collectors, by self-shading, walls and fences on rooftops, affect negatively the output energy of the PV systems. Increasing the distance between the collector rows, and between the walls and fences near to the collectors, may minimize the shading losses. Practically, this option is usually limited, especially on rooftops. Rooftops may be of different types: horizontal, inclined, and saw-tooth, and may have obscuring structures like walls and fences. The distance between the shading objects and the PV collector rows determine the loss of energy due to shading. The study provides the PV system designer with mathematical expressions for distances from obscuring objects for the deployment of PV systems on rooftops. The optimal inclination and azimuths angles of a PV system on a triangular sloped rooftop are also illustrated.

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