Environmental Engineering Reference
In-Depth Information
W
p
represents power consumed by the pump,
where
m
3
represents mass flow rate at
state 3,
v
3
represents specific volume at state 3,
P
4
represents pressure at state 4,
P
3
represents pressure at state 3 and
η
p
represents isentropic efficiency of the pump which
is considered to be 80%.
The rate of heat supplied to the boiler is taken to be the same as heat absorbed by
the air in the solar collector as shown below
˙
Q
bo
=
Q
so
(3.3.4)
The exergy destruction rate in the boiler is calculated as
Ex
4
+
Ex
bo
Ex
5
+
Ex
de,bo
=
(3.3.5)
where
m
4
(
h
4
s
0
)
Ex
4
=˙
−
h
0
)
−
T
0
(
s
4
−
1
T
0
T
bo
Ex
bo
=
Q
bo
−
T
4
+
T
5
T
bo
=
2
m
5
(
h
5
−
s
0
)
Ex
5
=˙
h
0
)
−
T
0
(
s
5
−
where
Ex
4
represents exergy rate at state 4,
Ex
bo
represents exergy rate carried by heat
Ex
5
represents exergy rate at state 5, and
Ex
de,bo
represents exergy
entering the boiler,
destruction rate in the boiler.
The power produced by the turbine is found using
W
t
=˙
−
m
5
(
h
5
h
6
)
(3.3.6)
W
t
represents power produced by the turbine,
where
m
5
represents mass flow rate at
state 5,
h
5
represents specific enthalpy at state 5, and
h
6
represents specific enthalpy
at state 6.
The exergy destruction rate in the turbine is calculated as
˙
Ex
5
Ex
6
+
Ex
de,t
W
t
=
+
(3.3.7)
where
m
5
(
h
5
s
0
)
Ex
5
=˙
−
h
0
)
−
T
0
(
s
5
−
m
6
(
h
6
s
0
)
Ex
6
=˙
−
h
0
)
−
T
0
(
s
6
−
where
Ex
5
represents exergy rate at stat 5,
Ex
6
represents exergy rate at state 6, and
Ex
de,t
represents exergy destruction rate in the turbine.
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