A6_calcShd: Shadows on PV systems.

Description

Compute the irradiance and irradiation including shadows for two-axis and horizontal N-S axis trackers and fixed surfaces. It makes use of the function fSombra for the shadows factor calculation. It is used by the function calcGef.

Usage

calcShd(radEf,
        modeShd = '',
        struct = list(),
        distances = data.table())

Value

A Gef object including three additional variables (Gef0, Def0 and Bef0) in the slots GefI,

GefD, Gefdm and Gefy with the irradiance/irradiation without shadows as a reference.

Arguments

radEf

A Gef object. It may be the result of the calcGef function.

modeShd

character, defines the type of shadow calculation. In this version of the package the effect of the shadow is calculated as a proportional reduction of the circumsolar diffuse and direct irradiances. This type of approach is selected with modeShd = 'area'. In future versions other approaches which relate the geometric shadow and the electrical connections of the PV generator will be available. If radEf@modeTrk = 'horiz' it is possible to calculate the effect of backtracking with modeShd = 'bt'. If modeShd = c('area','bt') the backtracking method will be carried out and therefore no shadows will appear. Finally, for two-axis trackers it is possible to select modeShd = 'prom' in order to calculate the effect of shadows on an average tracker (see fSombra6). The result will include three variables (Gef0, Def0 and Bef0) with the irradiance/irradiation without shadows as a reference.

struct

list.

When radEf@modeTrk = 'fixed' or modeTrk = 'horiz' only a component named L, which is the height (meters) of the tracker, is needed.

For two-axis trackers (radEf@modeTrk = 'two'), an additional component named W, the width of the tracker, is required. Moreover, only when radEf@modeTrk = 'two' two components named Nrow and Ncol are included under this list. These components define, respectively, the number of rows and columns of the whole set of two-axis trackers in the PV plant.

distances

data.frame.

When radEf@modeTrk = 'fixed' it includes a component named D for the distance between fixed surfaces. An additional component named H can be included with the relative height between surfaces.

When radEf@modeTrk = 'horiz' it only includes a component named Lew, being the distance between horizontal NS trackers along the East-West direction.

When radEf@modeTrk = 'two' it includes a component named Lns being the distance between trackers along the North-South direction, a component named Lew, being the distance between trackers along the East-West direction and a (optional) component named H with the relative height between surfaces.

The distances, in meters, are defined between axis of the trackers.

Author

Oscar Perpiñán Lamigueiro, Francisco Delgado López.

References