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@@ -0,0 +1,376 @@
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+
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+#define RAD2DEG 57.295779513 /* converts from radians to degrees */
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+#define DEG2RAD 0.0174532925 /* converts from degrees to radians */
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+
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+int dom2doy2(int year, int month, int day);
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+
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+ /*============================================================================
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+*
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+* NAME: solpos.h
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+*
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+* Contains:
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+* S_solpos (computes the solar position and intensity
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+* from time and place)
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+* INPUTS: (from posdata)
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+* year, month, day, hour, minute, second,
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+* latitude, longitude, timezone, interval
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+* OPTIONAL: (from posdata; defaults from S_init function)
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+* press DEFAULT 1013.0 (standard pressure)
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+* temp DEFAULT 10.0 (standard temperature)
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+* tilt DEFAULT 0.0 (horizontal panel)
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+* aspect DEFAULT 180.0 (South-facing panel)
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+* sbwid DEFAULT 7.6 (shadowband width)
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+* sbrad DEFAULT 31.7 (shadowband radius)
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+* sbsky DEFAULT 0.04 (shadowband sky factor)
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+*
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+* OUTPUTS: (posdata) daynum, amass, ampress, azim, cosinc,
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+* elevref, etr, etrn, etrtilt, prime,
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+* sbcf, sretr, ssetr, unprime, zenref
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+*
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+* RETURNS: Long int status code (defined in solpos.h)
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+*
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+* Usage:
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+* In calling program, along with other 'includes', insert:
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+*
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+* #include "solpos.h"
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+*
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+* Martin Rymes
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+* National Renewable Energy Laboratory
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+* 25 March 1998
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+*
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+*----------------------------------------------------------------------------*/
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+
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+/*============================================================================
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+*
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+* Define the function codes
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+*
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+*----------------------------------------------------------------------------*/
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+#define L_DOY 0x0001
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+#define L_GEOM 0x0002
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+#define L_ZENETR 0x0004
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+#define L_SSHA 0x0008
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+#define L_SBCF 0x0010
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+#define L_TST 0x0020
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+#define L_SRSS 0x0040
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+#define L_SOLAZM 0x0080
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+#define L_REFRAC 0x0100
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+#define L_AMASS 0x0200
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+#define L_PRIME 0x0400
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+#define L_TILT 0x0800
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+#define L_ETR 0x1000
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+#define L_ALL 0xFFFF
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+
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+/*============================================================================
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+*
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+* Define the bit-wise masks for each function
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+*
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+*----------------------------------------------------------------------------*/
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+#define S_DOY ( L_DOY )
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+#define S_GEOM ( L_GEOM | S_DOY )
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+#define S_ZENETR ( L_ZENETR | S_GEOM )
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+#define S_SSHA ( L_SSHA | S_GEOM )
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+#define S_SBCF ( L_SBCF | S_SSHA )
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+#define S_TST ( L_TST | S_GEOM )
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+#define S_SRSS ( L_SRSS | S_SSHA | S_TST )
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+#define S_SOLAZM ( L_SOLAZM | S_ZENETR )
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+#define S_REFRAC ( L_REFRAC | S_ZENETR )
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+#define S_AMASS ( L_AMASS | S_REFRAC )
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+#define S_PRIME ( L_PRIME | S_AMASS )
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+#define S_TILT ( L_TILT | S_SOLAZM | S_REFRAC )
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+#define S_ETR ( L_ETR | S_REFRAC )
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+#define S_ALL ( L_ALL )
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+
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+
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+/*============================================================================
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+*
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+* Enumerate the error codes
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+* (Bit positions are from least significant to most significant)
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+*
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+*----------------------------------------------------------------------------*/
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+/* Code Bit Parameter Range
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+ =============== === =================== ============= */
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+enum
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+{ S_YEAR_ERROR, /* 0 year 1950 - 2050 */
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+ S_MONTH_ERROR, /* 1 month 1 - 12 */
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+ S_DAY_ERROR, /* 2 day-of-month 1 - 31 */
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+ S_DOY_ERROR, /* 3 day-of-year 1 - 366 */
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+ S_HOUR_ERROR, /* 4 hour 0 - 24 */
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+ S_MINUTE_ERROR, /* 5 minute 0 - 59 */
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+ S_SECOND_ERROR, /* 6 second 0 - 59 */
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+ S_TZONE_ERROR, /* 7 time zone -12 - 12 */
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+ S_INTRVL_ERROR, /* 8 interval (seconds) 0 - 28800 */
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+ S_LAT_ERROR, /* 9 latitude -90 - 90 */
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+ S_LON_ERROR, /* 10 longitude -180 - 180 */
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+ S_TEMP_ERROR, /* 11 temperature (deg. C) -100 - 100 */
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+ S_PRESS_ERROR, /* 12 pressure (millibars) 0 - 2000 */
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+ S_TILT_ERROR, /* 13 tilt -90 - 90 */
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+ S_ASPECT_ERROR, /* 14 aspect -360 - 360 */
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+ S_SBWID_ERROR, /* 15 shadow band width (cm) 1 - 100 */
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+ S_SBRAD_ERROR, /* 16 shadow band radius (cm) 1 - 100 */
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+ S_SBSKY_ERROR
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+}; /* 17 shadow band sky factor -1 - 1 */
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+
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+struct posdata
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+{
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+
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+ /***** ALPHABETICAL LIST OF COMMON VARIABLES *****/
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+ /* Each comment begins with a 1-column letter code:
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+ I: INPUT variable
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+ O: OUTPUT variable
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+ T: TRANSITIONAL variable used in the algorithm,
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+ of interest only to the solar radiation
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+ modelers, and available to you because you
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+ may be one of them.
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+
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+ The FUNCTION column indicates which sub-function
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+ within solpos must be switched on using the
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+ "function" parameter to calculate the desired
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+ output variable. All function codes are
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+ defined in the solpos.h file. The default
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+ S_ALL switch calculates all output variables.
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+ Multiple functions may be or'd to create a
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+ composite function switch. For example,
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+ (S_TST | S_SBCF). Specifying only the functions
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+ for required output variables may allow solpos
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+ to execute more quickly.
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+
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+ The S_DOY mask works as a toggle between the
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+ input date represented as a day number (daynum)
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+ or as month and day. To set the switch (to
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+ use daynum input), the function is or'd; to
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+ clear the switch (to use month and day input),
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+ the function is inverted and and'd.
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+
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+ For example:
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+ pdat->function |= S_DOY (sets daynum input)
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+ pdat->function &= ~S_DOY (sets month and day input)
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+
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+ Whichever date form is used, S_solpos will
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+ calculate and return the variables(s) of the
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+ other form. See the soltest.c program for
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+ other examples. */
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+
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+ /* VARIABLE I/O Function Description */
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+ /* ------------- ---- ---------- --------------------------------------- */
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+
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+ int day; /* I/O: S_DOY Day of month (May 27 = 27, etc.)
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+ solpos will CALCULATE this by default,
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+ or will optionally require it as input
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+ depending on the setting of the S_DOY
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+ function switch. */
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+ int daynum; /* I/O: S_DOY Day number (day of year; Feb 1 = 32 )
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+ solpos REQUIRES this by default, but
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+ will optionally calculate it from
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+ month and day depending on the setting
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+ of the S_DOY function switch. */
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+ int function; /* I: Switch to choose functions for desired
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+ output. */
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+ int hour; /* I: Hour of day, 0 - 23, DEFAULT = 12 */
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+ int interval; /* I: Interval of a measurement period in
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+ seconds. Forces solpos to use the
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+ time and date from the interval
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+ midpoint. The INPUT time (hour,
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+ minute, and second) is assumed to
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+ be the END of the measurement
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+ interval. */
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+ int minute; /* I: Minute of hour, 0 - 59, DEFAULT = 0 */
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+ int month; /* I/O: S_DOY Month number (Jan = 1, Feb = 2, etc.)
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+ solpos will CALCULATE this by default,
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+ or will optionally require it as input
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+ depending on the setting of the S_DOY
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+ function switch. */
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+ int second; /* I: Second of minute, 0 - 59, DEFAULT = 0 */
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+ int year; /* I: 4-digit year (2-digit year is NOT
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+ allowed */
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+
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+ int time_updated; /* recalculate time-dependent variables */
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+ int longitude_updated; /* recalculate longitude-dependent variables */
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+
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+ /***** FLOATS *****/
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+
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+ float amass; /* O: S_AMASS Relative optical airmass */
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+ float ampress; /* O: S_AMASS Pressure-corrected airmass */
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+ float aspect; /* I: Azimuth of panel surface (direction it
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+ faces) N=0, E=90, S=180, W=270,
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+ DEFAULT = 180 */
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+ float azim; /* O: S_SOLAZM Solar azimuth angle: N=0, E=90, S=180,
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+ W=270 */
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+ float cosinc; /* O: S_TILT Cosine of solar incidence angle on
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+ panel */
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+ float coszen; /* O: S_REFRAC Cosine of refraction corrected solar
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+ zenith angle */
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+ float dayang; /* T: S_GEOM Day angle (daynum*360/year-length)
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+ degrees */
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+ float declin; /* T: S_GEOM Declination--zenith angle of solar noon
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+ at equator, degrees NORTH */
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+ float eclong; /* T: S_GEOM Ecliptic longitude, degrees */
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+ float ecobli; /* T: S_GEOM Obliquity of ecliptic */
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+ float ectime; /* T: S_GEOM Time of ecliptic calculations */
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+ float elevetr; /* O: S_ZENETR Solar elevation, no atmospheric
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+ correction (= ETR) */
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+ float elevref; /* O: S_REFRAC Solar elevation angle,
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+ deg. from horizon, refracted */
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+ float eqntim; /* T: S_TST Equation of time (TST - LMT), minutes */
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+ float erv; /* T: S_GEOM Earth radius vector
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+ (multiplied to solar constant) */
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+ float etr; /* O: S_ETR Extraterrestrial (top-of-atmosphere)
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+ W/sq m global horizontal solar
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+ irradiance */
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+ float etrn; /* O: S_ETR Extraterrestrial (top-of-atmosphere)
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+ W/sq m direct normal solar
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+ irradiance */
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+ float etrtilt; /* O: S_TILT Extraterrestrial (top-of-atmosphere)
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+ W/sq m global irradiance on a tilted
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+ surface */
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+ float gmst; /* T: S_GEOM Greenwich mean sidereal time, hours */
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+ float hrang; /* T: S_GEOM Hour angle--hour of sun from solar noon,
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+ degrees WEST */
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+ float julday; /* T: S_GEOM Julian Day of 1 JAN 2000 minus
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+ 2,400,000 days (in order to regain
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+ single precision) */
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+ float latitude; /* I: Latitude, degrees north (south negative) */
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+ float longitude; /* I: Longitude, degrees east (west negative) */
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+ float lmst; /* T: S_GEOM Local mean sidereal time, degrees */
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+ float mnanom; /* T: S_GEOM Mean anomaly, degrees */
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+ float mnlong; /* T: S_GEOM Mean longitude, degrees */
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+ float rascen; /* T: S_GEOM Right ascension, degrees */
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+ float press; /* I: Surface pressure, millibars, used for
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+ refraction correction and ampress */
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+ float prime; /* O: S_PRIME Factor that normalizes Kt, Kn, etc. */
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+ float sbcf; /* O: S_SBCF Shadow-band correction factor */
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+ float sbwid; /* I: Shadow-band width (cm) */
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+ float sbrad; /* I: Shadow-band radius (cm) */
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+ float sbsky; /* I: Shadow-band sky factor */
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+ float solcon; /* I: Solar constant (NREL uses 1367 W/sq m) */
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+ float ssha; /* T: S_SRHA Sunset(/rise) hour angle, degrees */
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+ float sretr; /* O: S_SRSS Sunrise time, minutes from midnight,
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+ local, WITHOUT refraction */
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+ float ssetr; /* O: S_SRSS Sunset time, minutes from midnight,
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+ local, WITHOUT refraction */
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+ float temp; /* I: Ambient dry-bulb temperature, degrees C,
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+ used for refraction correction */
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+ float tilt; /* I: Degrees tilt from horizontal of panel */
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+ float timezone; /* I: Time zone, east (west negative).
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+ USA: Mountain = -7, Central = -6, etc. */
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+ float tst; /* T: S_TST True solar time, minutes from midnight */
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+ float tstfix; /* T: S_TST True solar time - local standard time */
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+ float unprime; /* O: S_PRIME Factor that denormalizes Kt', Kn', etc. */
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+ float utime; /* T: S_GEOM Universal (Greenwich) standard time */
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+ float zenetr; /* T: S_ZENETR Solar zenith angle, no atmospheric
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+ correction (= ETR) */
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+ float zenref; /* O: S_REFRAC Solar zenith angle, deg. from zenith,
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+ refracted */
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+};
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+
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+/* For users that wish to access individual functions, the following table
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+ lists all output and transition variables, the L_ mask for the function
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+ that calculates them, and all the input variables required by that function.
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+ The function variable is set to the L_ mask, which will force S_solpos to
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+ only call the required function. L_ masks may be ORed as desired.
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+
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+ VARIABLE Mask Required Variables
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+ --------- ---------- ---------------------------------------
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+ amass L_AMASS zenref, press
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+ ampress L_AMASS zenref, press
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+ azim L_SOLAZM elevetr, declin, latitude, hrang
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+ cosinc L_TILT azim, aspect, tilt, zenref, coszen,etrn
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+ coszen L_REFRAC elevetr, press, temp
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+ dayang L_GEOM All date, time, and location inputs
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+ declin L_GEOM All date, time, and location inputs
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+ eclong L_GEOM All date, time, and location inputs
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+ ecobli L_GEOM All date, time, and location inputs
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+ ectime L_GEOM All date, time, and location inputs
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+ elevetr L_ZENETR declin, latitude, hrang
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+ elevref L_REFRAC elevetr, press, temp
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+ eqntim L_TST hrang, hour, minute, second, interval
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+ erv L_GEOM All date, time, and location inputs
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+ etr L_ETR coszen, solcon, erv
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+ etrn L_ETR coszen, solcon, erv
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+ etrtilt L_TILT azim, aspect, tilt, zenref, coszen, etrn
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+ gmst L_GEOM All date, time, and location inputs
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+ hrang L_GEOM All date, time, and location inputs
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+ julday L_GEOM All date, time, and location inputs
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+ lmst L_GEOM All date, time, and location inputs
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+ mnanom L_GEOM All date, time, and location inputs
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+ mnlong L_GEOM All date, time, and location inputs
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+ rascen L_GEOM All date, time, and location inputs
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+ prime L_PRIME amass
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+ sbcf L_SBCF latitude, declin, ssha, sbwid, sbrad, sbsky
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+ ssha L_SRHA latitude, declin
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+ sretr L_SRSS ssha, tstfix
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+ ssetr L_SRSS ssha, tstfix
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+ tst L_TST hrang, hour, minute, second, interval
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+ tstfix L_TST hrang, hour, minute, second, interval
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+ unprime L_PRIME amass
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+ utime L_GEOM All date, time, and location inputs
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+ zenetr L_ZENETR declination, latitude, hrang
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+ zenref L_REFRAC elevetr, press, temp
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+
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+ */
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+
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+/*============================================================================
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+* Long int function S_solpos, adapted from the NREL VAX solar libraries
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+*
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+* This function calculates the apparent solar position and intensity
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+* (theoretical maximum solar energy) based on the date, time, and
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+* location on Earth. (DEFAULT values are from the optional S_posinit
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+* function.)
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+*
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+* Requires:
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+* Date and time:
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+* year
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+* month (optional without daynum)
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+* day (optional without daynum)
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+* daynum
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+* hour
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+* minute
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+* second
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+* Location:
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+* latitude
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+* longitude
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+* Location/time adjuster:
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+* timezone
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+* Atmospheric pressure and temperature:
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+* press DEFAULT 1013.0 mb
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+* temp DEFAULT 10.0 degrees C
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+* Tilt of flat surface that receives solar energy:
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+* aspect DEFAULT 180 (South)
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+* tilt DEFAULT 0 (Horizontal)
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+* Shadow band parameters:
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+* sbwid DEFAULT 7.6 cm
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+* sbrad DEFAULT 31.7 cm
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+* sbsky DEFAULT 0.04
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+* Functionality
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+* function DEFAULT S_ALL (all output parameters computed)
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+*
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+* Returns:
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+* everything defined at the top of this listing.
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+*----------------------------------------------------------------------------*/
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+long S_solpos(struct posdata *pdat);
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+
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+/*============================================================================
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+* Void function S_init
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+*
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+* This function initiates all of the input functions to S_Solpos().
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+* NOTE: This function is optional if you initialize all input parameters
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+* in your calling code.
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+*
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+* Requires: Pointer to a posdata structure, members of which are
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+* initialized.
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+*
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+* Returns: Void
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+*
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+*----------------------------------------------------------------------------*/
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+void S_init(struct posdata *pdat);
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+
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+
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+/*============================================================================
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+* Void function S_decode
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+*
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+* This function decodes the error codes from S_solpos return value
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+*
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+* INPUTS: Long integer S_solpos return value, struct posdata*
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+*
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+* OUTPUTS: Descriptive text of errors to stderr
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+*----------------------------------------------------------------------------*/
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+void S_decode(long code, struct posdata *pdat);
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Markus Metz