solarAngles: Solar angles

In solaR2: Radiation and Photovoltaic Systems

Solar angles

Description

A set of functions that compute the apparent movement of the Sun from the Earth.

Usage

## Declination
declination(d, method = 'michalsky')

## Eccentricity
eccentricity(d, method = 'michalsky')

## Equation of time
eot(d)

## Solar time
sunrise(d, lat, method = 'michalsky',
        decl = declination(d, method = method))


## Extraterrestrial irradiation
bo0d(d, lat, method = 'michalsky',
     decl = declination(d, method = method),
     eo = eccentricity(d, method = method),
     ws = sunrise(d, lat, method = method))

## Sun hour angle
sunHour(d, BTi, sample = 'hour', EoT = TRUE,
        method = 'michalsky',
        eqtime = eot(d))

## Cosine of the zenith angle
zenith(d, lat, BTi, sample = 'hour', method = 'michalsky',
       decl = declination(d, method = method),
       w = sunHour(d, BTi, sample, method = method))

## Azimuth angle
azimuth(d, lat, BTi, sample = 'hour', method = 'michalsky',
        decl = declination(d, method = method),
        w = sunHour(d, BTi, sample, method = method),
        cosThzS = zenith(d, lat, BTi, sample,
                         method = method,
                         decl = decl,
                         w = w))

Arguments

d	Date, a daily time base, it may be the result of fBTd
method	character, method for the sun geometry calculations, to be chosen from 'cooper', 'spencer', 'michalsky' and 'strous'. See references for details.
lat	numeric, latitude (degrees) of the point of the Earth where calculations are needed. It is positive for locations above the Equator.
sample	Character, increment of the intradaily sequence.
BTi	POSIXct, intradily time base, it may the result of fBTi.
EoT	logical, if EoT=TRUE (default value), the function sunHour use the Equation of time
decl, eo, ws, eqtime, w, cosThzS	Arguments that compute the variables they reference (default value). It can be replaced with previously calculated values to avoid calculating the same variable twice.

Value

A vector with the calculated elements. Its size varies depending on whether the calculations are daily or intradaily.

Author(s)

Francisco Delgado López, Oscar Perpiñán Lamigueiro.

References

• Cooper, P.I., Solar Energy, 12, 3 (1969). "The Absorption of Solar Radiation in Solar Stills"

• Spencer, Search 2 (5), 172, https://www.mail-archive.com/[e-mail]/msg01050.html

• Strous: https://www.aa.quae.nl/en/reken/zonpositie.html

• Michalsky, J., 1988: The Astronomical Almanac's algorithm for approximate solar position (1950-2050), Solar Energy 40, 227-235

• Perpiñán, O, Energía Solar Fotovoltaica, 2015. (https://oscarperpinan.github.io/esf/)

• Perpiñán, O. (2012), "solaR: Solar Radiation and Photovoltaic Systems with R", Journal of Statistical Software, 50(9), 1-32, \Sexpr[results=rd]{tools:::Rd_expr_doi("10.18637/jss.v050.i09")}

See Also

fSolD, fSolI, calcSol

Examples

library("data.table")


d = fBTd(mode = 'serie')[100]

decl = declination(d, method = 'michalsky')
decl

w = sunHour(d, sample = 'hour', method = 'michalsky')
w

cosThzS = zenith(d, lat = 37.2, sample = 'hour',
                 method = 'michalsky',
                 decl = decl,
                 w = w)
cosThzS

solaR2 documentation built on April 3, 2025, 6:11 p.m.