pvlib.temperature.sapm_cell#

pvlib.temperature.sapm_cell(poa_global, temp_air, wind_speed, a, b, deltaT, irrad_ref=1000.0)[source]#

Calculate cell temperature per the Sandia Array Performance Model.

See [1] for details on the Sandia Array Performance Model.

Parameters:

poa_global (numeric) – Total incident irradiance [W/m^2].
temp_air (numeric) – Ambient dry bulb temperature [C].
wind_speed (numeric) – Wind speed at a height of 10 meters [m/s].
a (float) – Parameter \(a\) in (1).
b (float) – Parameter \(b\) in (1).
deltaT (float) – Parameter \(\Delta T\) in (2) [C].
irrad_ref (float, default 1000) – Reference irradiance, parameter \(E_{0}\) in (2) [W/m^2].

Returns:

numeric, values in degrees C.

Notes

The model for cell temperature \(T_{C}\) is given by a pair of equations (Eq. 11 and 12 in [1]).

(1)#\[T_{m} = E \times \exp (a + b \times WS) + T_{a}\]

(2)#\[T_{C} = T_{m} + \frac{E}{E_{0}} \Delta T\]

The module back surface temperature \(T_{m}\) is implemented in sapm_module().

Inputs to the model are plane-of-array irradiance \(E\) (W/m2) and ambient air temperature \(T_{a}\) (C). Model parameters depend both on the module construction and its mounting. Parameter sets are provided in [1] for representative modules and mounting, and are coded for convenience in TEMPERATURE_MODEL_PARAMETERS.

Module	Mounting	a	b	\(\Delta T [C]\)
glass/glass	open rack	-3.47	-0.0594	3
glass/glass	close mount	-2.98	-0.0471	1
glass/polymer	open rack	-3.56	-0.075	3
glass/polymer	insulated back	-2.81	-0.0455	0

Mounting cases can be described in terms of air flow across and around the rear-facing surface of the module:

“open rack” refers to mounting that allows relatively free air flow. This case is typical of ground-mounted systems on fixed racking or single axis trackers.
“close mount” refers to limited or restricted air flow. This case is typical of roof-mounted systems with some gap behind the module.
“insulated back” refers to systems with no air flow contacting the rear surface of the module. This case is typical of building-integrated PV systems, or systems laid flat on a ground surface.

References