def zhang_huang_solar(alt, cloud_cover, relative_humidity,<EOL>dry_bulb_present, dry_bulb_t3_hrs, wind_speed,<EOL>irr_0=<NUM_LIT>):
<EOL>C0, C1, C2, C3, C4, C5, D_COEFF, K_COEFF = <NUM_LIT>, <NUM_LIT>,-<NUM_LIT>, <NUM_LIT>, -<NUM_LIT>, <NUM_LIT>, -<NUM_LIT>, <NUM_LIT><EOL>glob_ir = <NUM_LIT:0><EOL>if alt > <NUM_LIT:0>:<EOL><INDENT>sin_alt = math.sin(math.radians(alt))<EOL>cc, rh, n_temp, n3_temp, w_spd = cloud_cover / <NUM_LIT>,relative_humidity, dry_bulb_present, dry_bulb_t3_hrs, wind_speed<EOL>glob_ir = ((irr_0 * sin_alt *<EOL>(C0 + (C1 * cc) + (C2 * cc**<NUM_LIT:2>) +<EOL>(C3 * (n_temp - n3_temp)) +<EOL>(C4 * rh) + (C5 * w_spd))) + D_COEFF) / K_COEFF<EOL>if glob_ir < <NUM_LIT:0>:<EOL><INDENT>glob_ir = <NUM_LIT:0><EOL><DEDENT><DEDENT>return glob_ir<EOL>
Calculate global horizontal solar irradiance using the Zhang-Huang model.

    Note:
        [1] Zhang, Q.Y. and Huang, Y.J. 2002. "Development of typical year weather files
        for Chinese locations", LBNL-51436, ASHRAE Transactions, Vol. 108, Part 2.

    Args:
        alt: A solar altitude in degrees.
        cloud_cover: A float value between 0 and 10 that represents the sky cloud cover
            in tenths (0 = clear; 10 = completely overcast)
        relative_humidity: A float value between 0 and 100 that represents
            the relative humidity in percent.
        dry_bulb_present: A float value that represents the dry bulb
            temperature at the time of interest (in degrees C).
        dry_bulb_t3_hrs: A float value that represents the dry bulb
            temperature at three hours before the time of interest (in degrees C).
        wind_speed: A float value that represents the wind speed in m/s.
        irr_0 = Optional extraterrestrial solar constant (W/m2).
            Default is to use the average value over the earth's orbit (1355).

    Returns:
        glob_ir: A global horizontall radiation value in W/m2.