solaR (version 0.14)

fSolD: Daily apparent movement of the Sun from the Earth

Description

Compute the daily apparent movement of the Sun from the Earth. This movement is mainly described (for the simulation of photovoltaic systems) by the declination angle, the sunset angle and the daily extra-atmospheric irradiation.

Usage

fSolD(lat,dn, BTd)

Arguments

lat

Latitude (degrees) of the point of the Earth where calculations are needed. It is positive for locations above the Equator.

dn

Day of year as decimal number (1:366). It can be a unique number, a range of days or a set of individual ones.

BTd

Daily temporal base, data.frame which includes the variables Ano (year), DiaAno (day of year), Mes (month) and DiaMes (day of month). It may be the result of fBTd

Value

• A data.frame with these components:
• BTd
  data.frame, only when this argument was included in the call to this function
• IDd
  numeric, a value which identifies each day of the time series. It is only included when the dn argument was supplied.
• DiaAno
  numeric, the value of dn. It is only included when the dn argument was supplied.
• lat
  Latitude, now converted to radians.
• decl
  Declination angle (radians) for each day of year in dn or BTd
• eo
  Factor of correction due the eccentricity of orbit of the Earth around the Sun.
• ws
  Sunset angle (in radians) for each day of year. Due to the convention which considers that the solar hour angle is negative before midday, this angle is negative.
• Bo0d
  Extra-atmospheric daily irradiation (watt-hour per squared meter) incident on a horizontal surface

encoding

UTF-8

References

Perpiñán, O, Energía Solar Fotovoltaica, 2010. (http://procomun.wordpress.com/documentos/libroesf/)

Examples

lat=37.2
(fSolD(lat,dn=100))

lat=-37.2
(fSolD(lat,dn=283))

#Declination angle along the year
SolD<-fSolD(lat,BTd=fBTd())
library(lattice)
xyplot(decl~DiaAno,data=SolD,type='l')

#Calculation of the daylength for several latitudes
SolD<-data.frame()
for (i in c(-60,-40,-20,0,20,40,60)){
    if (i>0) {NomLat=paste(i,'N',sep='')} else 
    if (i<0) {NomLat=paste(abs(i),'S',sep='')} else NomLat="0";
    SolDaux<-fSolD(lat=i,BTd=fBTd(Modo='Serie'));
    SolD<-rbind(SolD,data.frame(SolDaux,Lat=NomLat));}
    
p<-xyplot(12/pi*2*abs(ws)~DiaAno,
        data=SolD,groups=factor(Lat), 
        xlab='dn',ylab=expression(omega[s] (h)), 
        type='l')

library(latticedl)
print(direct.label(p,method=last.points));