diff --git a/docs/sphinx/source/whatsnew/v0.11.2.rst b/docs/sphinx/source/whatsnew/v0.11.2.rst index 918dcc18d..81d36fda6 100644 --- a/docs/sphinx/source/whatsnew/v0.11.2.rst +++ b/docs/sphinx/source/whatsnew/v0.11.2.rst @@ -16,7 +16,8 @@ Documentation ~~~~~~~~~~~~~ * Edited docstrings for :py:func:`~pvlib.pvsystem.dc_ohms_from_percent` and :py:func:`~pvlib.pvsystem.dc_ohmic_losses` for clarity. (:issue:`1601`, :pull:`2229`) - +* Updated :py:func:`~pvlib.irradiance.reindl` to include definitions of terms + and a new "notes" section (:issue:`2183`, :pull:`2193`) Testing ~~~~~~~ @@ -29,4 +30,5 @@ Requirements Contributors ~~~~~~~~~~~~ * Cliff Hansen (:ghuser:`cwhanse`) +* Rajiv Daxini (:ghuser:`RDaxini`) diff --git a/pvlib/irradiance.py b/pvlib/irradiance.py index db6243977..d1854cfb6 100644 --- a/pvlib/irradiance.py +++ b/pvlib/irradiance.py @@ -871,19 +871,14 @@ def haydavies(surface_tilt, surface_azimuth, dhi, dni, dni_extra, def reindl(surface_tilt, surface_azimuth, dhi, dni, ghi, dni_extra, solar_zenith, solar_azimuth): r''' - Determine diffuse irradiance from the sky on a tilted surface using - Reindl's 1990 model - - .. math:: + Determine the diffuse irradiance from the sky on a tilted surface using + the Reindl (1990) model. - I_{d} = DHI \left(A R_b + (1 - A) \left(\frac{1 + \cos\beta}{2}\right) - \left(1 + \sqrt{\frac{I_{hb}}{I_h}} \sin^3(\beta/2)\right) \right) - - Reindl's 1990 model determines the diffuse irradiance from the sky - (ground reflected irradiance is not included in this algorithm) on a - tilted surface using the surface tilt angle, surface azimuth angle, + The Reindl (1990) model [1]_ [2]_ determines the diffuse irradiance from + the sky on + a tilted surface using the surface tilt angle, surface azimuth angle, diffuse horizontal irradiance, direct normal irradiance, global - horizontal irradiance, extraterrestrial irradiance, sun zenith + horizontal irradiance, extraterrestrial normal irradiance, sun zenith angle, and sun azimuth angle. Parameters @@ -905,7 +900,7 @@ def reindl(surface_tilt, surface_azimuth, dhi, dni, ghi, dni_extra, direct normal irradiance. [Wm⁻²] ghi: numeric - Global irradiance. [Wm⁻²] + Global horizontal irradiance. [Wm⁻²] dni_extra : numeric Extraterrestrial normal irradiance. [Wm⁻²] @@ -925,23 +920,41 @@ def reindl(surface_tilt, surface_azimuth, dhi, dni, ghi, dni_extra, Notes ----- - The poa_sky_diffuse calculation is generated from the Loutzenhiser et al. - (2007) paper, equation 8. Note that I have removed the beam and ground - reflectance portion of the equation and this generates ONLY the diffuse - radiation from the sky and circumsolar, so the form of the equation - varies slightly from equation 8. + The Reindl (1990) model for the sky diffuse irradiance, + :math:`I_d`, is as follows: + + .. math:: + + I_{d} = DHI \left(A \cdot R_b + (1 - A) + \left(\frac{1 + \cos\beta}{2}\right) + \left(1 + \sqrt{\frac{BHI}{GHI}} \sin^3(\beta/2)\right) \right). + + :math:`DHI`, :math:`BHI`, and :math:`GHI` are the diffuse horizontal, beam + (direct) horizontal and global horizontal irradiances, respectively. + :math:`A` is the anisotropy index, which is the ratio of the direct normal + irradiance to the direct extraterrestrial irradiation, :math:`R_b` is the + projection ratio, which is defined as the ratio of the cosine of the angle + of incidence (AOI) to the cosine of the zenith angle, and :math:`\beta` + is the tilt angle of the array. + + Implementation is based on Loutzenhiser et al. + (2007) [3]_, Equation 8. The beam and ground reflectance portion of the + equation have been removed, therefore the model described here generates + ONLY the diffuse radiation from the sky and circumsolar, so the form of the + equation varies slightly from Equation 8 in [3]_. References ---------- - .. [1] Loutzenhiser P.G. et. al. "Empirical validation of models to - compute solar irradiance on inclined surfaces for building energy - simulation" 2007, Solar Energy vol. 81. pp. 254-267 - - .. [2] Reindl, D.T., Beckmann, W.A., Duffie, J.A., 1990a. Diffuse + .. [1] Reindl, D. T., Beckmann, W. A., Duffie, J. A., 1990a. Diffuse fraction correlations. Solar Energy 45(1), 1-7. - - .. [3] Reindl, D.T., Beckmann, W.A., Duffie, J.A., 1990b. Evaluation of + :doi:`10.1016/0038-092X(90)90060-P` + .. [2] Reindl, D. T., Beckmann, W. A., Duffie, J. A., 1990b. Evaluation of hourly tilted surface radiation models. Solar Energy 45(1), 9-17. + :doi:`10.1016/0038-092X(90)90061-G` + .. [3] Loutzenhiser P. G. et. al., 2007. Empirical validation of models to + compute solar irradiance on inclined surfaces for building energy + simulation. Solar Energy 81(2), 254-267 + :doi:`10.1016/j.solener.2006.03.009` ''' cos_tt = aoi_projection(surface_tilt, surface_azimuth,