Page 212 - Design of Solar Thermal Power Plants

196 3. GENERAL DESIGN OF A SOLAR THERMAL POWER PLANT

FIGURE 3.45 Annual power generation calculation process.

Thermal storage capacity normally depends on the night peak modu-
lation power supply capacity (product of power and generation hours). In
case of only focusing on night power generation, concentration field area
shall satisfy the rated thermal request of steam turbine corresponding to
night generation hours. However, such operational condition has been
rarely seen. In case of no thermal storage, output of concentration field at
the design point is the rated input of steam turbine.
Step I: The design point irradiation and meteorological conditions, and
the steam turbine rated power P TURBINE are defined.
Step II: The concentration field area is assumed to be A.
Step III: Power plant output power at the design point can be calcu-
lated according to the process described in Table 3.1. In case that P
satisfies:
jP P TURBINCE j < ε (3.76)
Then the calculation process ends, and concentration field area A is
obtained. Otherwise, a new concentration field area shall be assumed for
another calculation, until Eq. (3.76) is satisfied. ε refers to the allowed
margin of error of iteration, which shall be determined before calculation,
such as ε ¼ 50 kW.
System photoelectric efficiency h at the design point is calculated as
2
follows: assuming DNI ¼ 1000 w/m at the design point
P TURBINE
h ¼ (3.77)
1000 A