Civil Engineering Reference
In-Depth Information
efficiency temperature coefficients (
) for various BIPV technologies
mono-Si −0.24 to −0.48 13.5 (PikeResearch, 2012)
poly-Si −0.41 to −0.50 12 (PikeResearch, 2012)
Silicon Heterostructures (HIT) −0.3
18.3
Thin film
a-Si
−0.21 to −0.28 7 (PikeResearch, 2012)
Micromorph
−0.20 to −0.36 9
Cu(In,Ga)Se
2
(CIGS)
−0.31 to −0.53 16.6 (PikeResearch, 2012)
CdTe
−0.25
11.7 (PikeResearch, 2012)
Organic (OPV)
+0.05
5 (PikeResearch, 2012)
Other electrical models include the equivalent one-diode model (Duffie and
Beckman, 2006) and King's model (King, Boyson, and Kratochvil, 2004).
As the model becomes more complex, its accuracy tends to be better, but
the number of required parameters increases. In addition to incident solar
radiation, models typically require the PV cell temperature and a number
of empirically determined parameters available in databases or provided by
manufacturers.
A widely used model that is implemented in several simulation tools, such
as PVsyst (2012) and EnergyPlus, is the equivalent one-diode model.
This model requires as inputs the open circuit voltage (
V
oc
), short-circuit
current (
I
sc
), current (
I
mp
), and voltage (
V
mp
) at maximum power point
as well as the temperature coefficients for short-circuit current ( ) and
open-circuit voltage ( ), under reference conditions. These parameters
can be found in manufacturer technical specification sheets.
The module current (
I
) is the resultant of the photo current (
I
ph
), the
equivalent diode current representing the voltage-dependent current lost
to recombination (
I
D
), and the parasitic shunt current (
I
sh
). In order to
determine the PV performance under operating conditions, the diode
reverse saturation current (
I
o
), the series resistance (
R
s
), the shunt
resistance (
R
sh
), and the curve fitting parameter (
a
) should be obtained.
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