shows the annual SEE variation with different solar field
aperture areas, TES hours and turbine loads. For a SACPG system
without TES, with solar field aperture area increasing, the annual
SEE first rises, reaches the maximum value and then decreases.
The reason is that, with solar field aperture area increasing, more
extraction steam of higher grade would be replaced in the order
of HP3, HP2 and HP1. After the HP extraction steam is totally
replaced, the surplus solar heat would not be used as there is no
TES system, resulting the decrease of the annual SEE. For a
SACPG system with TES, with solar field aperture area increasing,
the annual SEE starts at the maximum values until the surplus
solar heat is over the storage capacity.
Another point to be noted in Fig. 8 is that with turbine load
decreasing, the peak SEE with the same storage capacity decreases
(shift to the left). It is because the solar electrical power output in
partial load operation is lower than that in full load operation (concluded
in Section 4.4.2).