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Mon Apr 9 21:33:35 2012 UTC (10 years, 2 months ago) by jpye
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Add original downloaded versions of NREL sunpos code.
1
2
3 /////////////////////////////////////////////
4 // HEADER FILE for SPA.C //
5 // //
6 // Solar Position Algorithm (SPA) //
7 // for //
8 // Solar Radiation Application //
9 // //
10 // May 12, 2003 //
11 // //
12 // Filename: SPA.H //
13 // //
14 // Afshin Michael Andreas //
15 // afshin_andreas@nrel.gov (303)384-6383 //
16 // //
17 // Measurement & Instrumentation Team //
18 // Solar Radiation Research Laboratory //
19 // National Renewable Energy Laboratory //
20 // 1617 Cole Blvd, Golden, CO 80401 //
21 /////////////////////////////////////////////
22
23 ////////////////////////////////////////////////////////////////////////
24 // //
25 // Usage: //
26 // //
27 // 1) In calling program, include this header file, //
28 // by adding this line to the top of file: //
29 // #include "spa.h" //
30 // //
31 // 2) In calling program, declare the SPA structure: //
32 // spa_data spa; //
33 // //
34 // 3) Enter the required input values into SPA structure //
35 // (input values listed in comments below) //
36 // //
37 // 4) Call the SPA calculate function and pass the SPA structure //
38 // (prototype is declared at the end of this header file): //
39 // spa_calculate(&spa); //
40 // //
41 // Selected output values (listed in comments below) will be //
42 // computed and returned in the passed SPA structure. Output //
43 // will based on function code selected from enumeration below. //
44 // //
45 // Note: A non-zero return code from spa_calculate() indicates that //
46 // one of the input values did not pass simple bounds tests. //
47 // The valid input ranges and return error codes are also //
48 // listed below. //
49 // //
50 ////////////////////////////////////////////////////////////////////////
51
52 #ifndef __solar_position_algorithm_header
53 #define __solar_position_algorithm_header
54
55
56 //enumeration for function codes to select desired final outputs from SPA
57 enum {
58 SPA_ZA, //calculate zenith and azimuth
59 SPA_ZA_INC, //calculate zenith, azimuth, and incidence
60 SPA_ZA_RTS, //calculate zenith, azimuth, and sun rise/transit/set values
61 SPA_ALL, //calculate all SPA output values
62 };
63
64 typedef struct
65 {
66 //----------------------INPUT VALUES------------------------
67
68 int year; // 4-digit year, valid range: -2000 to 6000, error code: 1
69 int month; // 2-digit month, valid range: 1 to 12, error code: 2
70 int day; // 2-digit day, valid range: 1 to 31, error code: 3
71 int hour; // Observer local hour, valid range: 0 to 24, error code: 4
72 int minute; // Observer local minute, valid range: 0 to 59, error code: 5
73 int second; // Observer local second, valid range: 0 to 59, error code: 6
74
75 double delta_t; // Difference between earth rotation time and terrestrial time
76 // It is derived from observation only and is reported in this
77 // bulletin: http://maia.usno.navy.mil/ser7/ser7.dat,
78 // where delta_t = 32.184 + (TAI-UTC) + DUT1
79 // valid range: -8000 to 8000 seconds, error code: 7
80
81 double timezone; // Observer time zone (negative west of Greenwich)
82 // valid range: -18 to 18 hours, error code: 8
83
84 double longitude; // Observer longitude (negative west of Greenwich)
85 // valid range: -180 to 180 degrees, error code: 9
86
87 double latitude; // Observer latitude (negative south of equator)
88 // valid range: -90 to 90 degrees, error code: 10
89
90 double elevation; // Observer elevation [meters]
91 // valid range: -6500000 or higher meters, error code: 11
92
93 double pressure; // Annual average local pressure [millibars]
94 // valid range: 0 to 5000 millibars, error code: 12
95
96 double temperature; // Annual average local temperature [degrees Celsius]
97 // valid range: -273 to 6000 degrees Celsius, error code; 13
98
99 double slope; // Surface slope (measured from the horizontal plane)
100 // valid range: -360 to 360 degrees, error code: 14
101
102 double azm_rotation; // Surface azimuth rotation (measured from south to projection of
103 // surface normal on horizontal plane, negative west)
104 // valid range: -360 to 360 degrees, error code: 15
105
106 double atmos_refract;// Atmospheric refraction at sunrise and sunset (0.5667 deg is typical)
107 // valid range: -5 to 5 degrees, error code: 16
108
109 int function; // Switch to choose functions for desired output (from enumeration)
110
111 //-----------------Intermediate OUTPUT VALUES--------------------
112
113 double jd; //Julian day
114 double jc; //Julian century
115
116 double jde; //Julian ephemeris day
117 double jce; //Julian ephemeris century
118 double jme; //Julian ephemeris millennium
119
120 double l; //earth heliocentric longitude [degrees]
121 double b; //earth heliocentric latitude [degrees]
122 double r; //earth radius vector [Astronomical Units, AU]
123
124 double theta; //geocentric longitude [degrees]
125 double beta; //geocentric latitude [degrees]
126
127 double x0; //mean elongation (moon-sun) [degrees]
128 double x1; //mean anomaly (sun) [degrees]
129 double x2; //mean anomaly (moon) [degrees]
130 double x3; //argument latitude (moon) [degrees]
131 double x4; //ascending longitude (moon) [degrees]
132
133 double del_psi; //nutation longitude [degrees]
134 double del_epsilon; //nutation obliquity [degrees]
135 double epsilon0; //ecliptic mean obliquity [arc seconds]
136 double epsilon; //ecliptic true obliquity [degrees]
137
138 double del_tau; //aberration correction [degrees]
139 double lamda; //apparent sun longitude [degrees]
140 double nu0; //Greenwich mean sidereal time [degrees]
141 double nu; //Greenwich sidereal time [degrees]
142
143 double alpha; //geocentric sun right ascension [degrees]
144 double delta; //geocentric sun declination [degrees]
145
146 double h; //observer hour angle [degrees]
147 double xi; //sun equatorial horizontal parallax [degrees]
148 double del_alpha; //sun right ascension parallax [degrees]
149 double delta_prime; //topocentric sun declination [degrees]
150 double alpha_prime; //topocentric sun right ascension [degrees]
151 double h_prime; //topocentric local hour angle [degrees]
152
153 double e0; //topocentric elevation angle (uncorrected) [degrees]
154 double del_e; //atmospheric refraction correction [degrees]
155 double e; //topocentric elevation angle (corrected) [degrees]
156
157 double eot; //equation of time [minutes]
158 double srha; //sunrise hour angle [degrees]
159 double ssha; //sunset hour angle [degrees]
160 double sta; //sun transit altitude [degrees]
161
162 //---------------------Final OUTPUT VALUES------------------------
163
164 double zenith; //topocentric zenith angle [degrees]
165 double azimuth180; //topocentric azimuth angle (westward from south) [-180 to 180 degrees]
166 double azimuth; //topocentric azimuth angle (eastward from north) [ 0 to 360 degrees]
167 double incidence; //surface incidence angle [degrees]
168
169 double suntransit; //local sun transit time (or solar noon) [fractional hour]
170 double sunrise; //local sunrise time (+/- 30 seconds) [fractional hour]
171 double sunset; //local sunset time (+/- 30 seconds) [fractional hour]
172
173 } spa_data;
174
175 //Calculate SPA output values (in structure) based on input values passed in structure
176 int spa_calculate(spa_data *spa);
177
178 #endif

john.pye@anu.edu.au
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