
497Solar Process Heat and Thermal Power
© 2008 Taylor & Francis Group, LLC
temperature T, 300 K for the ambient (T
a
), and 0.88 for ε (typical for rough oxidized steel),
and an empirical relation of c = 5 W/m
2
K
125
, the thermal loss, T
L
, from the receiver is
TA TT cT T
T
L receivera
t
a
L
=−
+−
=⋅×
εσ
4125
1 056 088567 10
()
,..
.
−−
−+−
=+
[]
=
84
25
800 300 5 800 300
1 056 20 000 11 600
.( )( )
,, ,
.
T
L
331 6. MW
(8.53)
The resulting thermal efciency is
η
η
th
th
=− =−
+
=−
=
1
31 6
093
incident power
DPTO
L
.
.77937= .%
(8.54)
The required collector (heliostat) area at the design point is given by
Absorbed solar power DPTOP + TL CSB ==GpAT
c
(8.55)
Hen ...