pvl_martinruiziam
Determine the incidence angle modifier using the Martin and Ruiz model.
Contents
Syntax
- IAM = pvl_martinruiziam(ar, theta)
Description:
pvl_martinruiziam calculates the incidence angle modifier (IAM) as described in [1] and clarified in [2]. The incidence angle modifier quantifies the fraction of direct irradiance incidence on a module's surface that is not reflected away. The incidence angle modifier is computed as
,
Thus at
, and
at
.
Inputs
- ar - The angular losses coefficient described in equation 3 of [1]. ar is an empirical dimensionless parameter with values generally on the order of 0.08 to 0.25 for flat-plate PV modules. ar must be a numeric scalar or vector with all values > 0. If ar is a vector, it must be the same size as all other input vectors.
- theta - The angle of incidence between the module normal vector and the sun vector in degrees. theta must be a numeric scalar or vector. For any values of theta where abs(theta)>90, IAM is set to 0. For any values of theta where -90 < theta < 0, theta is set to abs(theta) and evaluated. A warning will be generated if any(theta<0 or theta>90).
Output
- IAM - The incident angle modifier. IAM is a column vector with the same number of elements as the largest input vector.
Example
This example plots the IAM for glass over a range of incident angles.
ar = 0.15; % empirical losses coefficient of 0.15 theta = 0:90; %incident angle in degrees IAM = pvl_martinruiziam(ar, theta); figure plot(theta,IAM) xlabel('Incident Angle (deg)') ylabel('IAM') title('Martin and Ruiz IAM Model Example')

References
[1] N. Martin and J. M. Ruiz, 2001. Calculation of the PV modules angular losses under field conditions by means of an analytical model, Solar Energy Materials & Solar Cells, vol. 70, pp. 25-38.
[2] N. Martin and J. M. Ruiz, 2013. Corrigendum to 'Calculation of the PV modules angular losses under field conditions by means of an analytical model', Solar Energy Materials & Solar Cells, vol. 110, pp. 154.
See also
pvl_getaoi , pvl_ephemeris , pvl_spa , pvl_ashraeiam , pvl_physicaliam
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