Environmental Engineering Reference
In-Depth Information
Table 3.3.1
Solar PV/T parameters.
Parameter
Values
100m
2
A
B
0.45m
h
p1
0.88
L
1.2m
0.83
β
c
0.12
η
c
0.95
τ
g
0.62W/m
2
K
U
b
U
t
2.8W/m
2
K
0.90
α
c
increases. The heated air leaving the duct can be used for different heating and cooling
purposes based on the temperature of the air leaving the duct and the operating system.
3.3.2.2 Energy and exergy analyses
The equations which are used to solve the mathematical model of the PV/T system
are derived from Joshi et al. (2009a, and 2009b). Moreover, the assumptions and
constants of solar PV/T system are listed in Table 3.3.1.
The equation to calculate power produced by the PV module is given as
W
so
=
η
c
×
I
×
β
c
×
τ
g
×
A
(3.3.12)
where
W
so
represents power produced by the solar panel,
η
c
represents cell efficiency,
I
represents solar flux,
β
c
represents the packing factor of the solar cell,
τ
g
represents
transitivity of glass, and
A
represents the area of the solar PV/T system
The heat transfer rate from solar panels to air passing through the duct is given by
1
exp
−
×
(
h
p2G
×
I
−
m
a
×
˙
cp
a
b
×
U
L
×
L
Q
so
=
z
×
U
L
×
(
T
ai
−
T
0
))
×
−
U
L
m
a
×
˙
cp
a
(3.3.13)
where
=
α
b
×
τ
g
×
z
(1
−
β
c
)
+
h
p1G
×
τ
g
×
β
c
×
(
α
c
−
η
c
)
Q
so
represents heat transfer rate from PV panels to air,
where
m
a
represents mass flow
rate of air,
cp
a
represents specific heat at constant pressure of air,
U
L
represents overall
heat transfer coefficient from solar cell to ambient through the top and back surface of
the insulation,
h
p2G
represents a penalty factor due to presence of an interface between
glass and working fluid through an absorber plate for a glass-to-glass PV/T system,
z
represents a variable,
T
ai
represents temperature of air entering the duct,
T
0
represents
ambient temperature,
b
represents breadth of the single PV panel,
L
represents length
of the single PV panel,
α
b
represents absorptance of a painted black surface,
h
p1G
˙
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