@@ -869,19 +869,14 @@ def haydavies(surface_tilt, surface_azimuth, dhi, dni, dni_extra,
869869def reindl (surface_tilt , surface_azimuth , dhi , dni , ghi , dni_extra ,
870870 solar_zenith , solar_azimuth ):
871871 r'''
872- Determine diffuse irradiance from the sky on a tilted surface using
873- Reindl's 1990 model
874-
875- .. math::
872+ Determine the diffuse irradiance from the sky on a tilted surface using
873+ the Reindl (1990) model.
876874
877- I_{d} = DHI \left(A R_b + (1 - A) \left(\frac{1 + \cos\beta}{2}\right)
878- \left(1 + \sqrt{\frac{I_{hb}}{I_h}} \sin^3(\beta/2)\right) \right)
879-
880- Reindl's 1990 model determines the diffuse irradiance from the sky
881- (ground reflected irradiance is not included in this algorithm) on a
882- tilted surface using the surface tilt angle, surface azimuth angle,
875+ The Reindl (1990) model [1]_ [2]_ determines the diffuse irradiance from
876+ the sky on
877+ a tilted surface using the surface tilt angle, surface azimuth angle,
883878 diffuse horizontal irradiance, direct normal irradiance, global
884- horizontal irradiance, extraterrestrial irradiance, sun zenith
879+ horizontal irradiance, extraterrestrial normal irradiance, sun zenith
885880 angle, and sun azimuth angle.
886881
887882 Parameters
@@ -903,7 +898,7 @@ def reindl(surface_tilt, surface_azimuth, dhi, dni, ghi, dni_extra,
903898 direct normal irradiance. [Wm⁻²]
904899
905900 ghi: numeric
906- Global irradiance. [Wm⁻²]
901+ Global horizontal irradiance. [Wm⁻²]
907902
908903 dni_extra : numeric
909904 Extraterrestrial normal irradiance. [Wm⁻²]
@@ -923,23 +918,41 @@ def reindl(surface_tilt, surface_azimuth, dhi, dni, ghi, dni_extra,
923918
924919 Notes
925920 -----
926- The poa_sky_diffuse calculation is generated from the Loutzenhiser et al.
927- (2007) paper, equation 8. Note that I have removed the beam and ground
928- reflectance portion of the equation and this generates ONLY the diffuse
929- radiation from the sky and circumsolar, so the form of the equation
930- varies slightly from equation 8.
921+ The Reindl (1990) model for the sky diffuse irradiance,
922+ :math:`I_d`, is as follows:
923+
924+ .. math::
925+
926+ I_{d} = DHI \left(A \cdot R_b + (1 - A)
927+ \left(\frac{1 + \cos\beta}{2}\right)
928+ \left(1 + \sqrt{\frac{BHI}{GHI}} \sin^3(\beta/2)\right) \right).
929+
930+ :math:`DHI`, :math:`BHI`, and :math:`GHI` are the diffuse horizontal, beam
931+ (direct) horizontal and global horizontal irradiances, respectively.
932+ :math:`A` is the anisotropy index, which is the ratio of the direct normal
933+ irradiance to the direct extraterrestrial irradiation, :math:`R_b` is the
934+ projection ratio, which is defined as the ratio of the cosine of the angle
935+ of incidence (AOI) to the cosine of the zenith angle, and :math:`\beta`
936+ is the tilt angle of the array.
937+
938+ Implementation is based on Loutzenhiser et al.
939+ (2007) [3]_, Equation 8. The beam and ground reflectance portion of the
940+ equation have been removed, therefore the model described here generates
941+ ONLY the diffuse radiation from the sky and circumsolar, so the form of the
942+ equation varies slightly from Equation 8 in [3]_.
931943
932944 References
933945 ----------
934- .. [1] Loutzenhiser P.G. et. al. "Empirical validation of models to
935- compute solar irradiance on inclined surfaces for building energy
936- simulation" 2007, Solar Energy vol. 81. pp. 254-267
937-
938- .. [2] Reindl, D.T., Beckmann, W.A., Duffie, J.A., 1990a. Diffuse
946+ .. [1] Reindl, D. T., Beckmann, W. A., Duffie, J. A., 1990a. Diffuse
939947 fraction correlations. Solar Energy 45(1), 1-7.
940-
941- .. [3 ] Reindl, D.T., Beckmann, W.A., Duffie, J.A., 1990b. Evaluation of
948+ :doi:`10.1016/0038-092X(90)90060-P`
949+ .. [2 ] Reindl, D. T., Beckmann, W. A., Duffie, J. A., 1990b. Evaluation of
942950 hourly tilted surface radiation models. Solar Energy 45(1), 9-17.
951+ :doi:`10.1016/0038-092X(90)90061-G`
952+ .. [3] Loutzenhiser P. G. et. al., 2007. Empirical validation of models to
953+ compute solar irradiance on inclined surfaces for building energy
954+ simulation. Solar Energy 81(2), 254-267
955+ :doi:`10.1016/j.solener.2006.03.009`
943956 '''
944957
945958 cos_tt = aoi_projection (surface_tilt , surface_azimuth ,
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