Page 213 - Design of Solar Thermal Power Plants

3.7 CALCULATION OF ANNUAL POWER GENERATION 197

FIGURE 3.46 Determination of thermal storage and concentrating area.

In case of substituting the annual mean efficiency with the photoelec-
tric efficiency of the system, the annual power generation E can be
calculated as follows:
E ¼ DNI A h (3.78)
In case of the system being equipped with a thermal storage, after
determining the corresponding concentration field area of steam turbine,
the corresponding concentration field area of thermal storage can be
calculated, which is shown in Fig. 3.46. Thermal storage is calculated in a
different way with thermal radiation in the denomination of “day.” For a
system equipped with a thermal storage, the total area of the concentra-
tion field equals to the sum of the concentration field area calculated
according to Fig. 3.45 corresponding to the steam turbine and the required
concentration field area corresponding to thermal storage.

3.7.2 Calculation Example for Annual Power Generation
It is known that in a certain location, the annual total
2
2
DNI ¼ 1850 kWh/m , annual mean solar irradiance is 750 W/m , and
annual mean ambient air temperature is 10 C. Steam turbine parameters

of the 50 MW power tower plant equipped with 4 h thermal storage are
shown in Table 3.9.
Provided that thermal energy is accumulated through 4 h of full-load
operation of steam turbine, the heliostat concentration field area and
annual power generation of power plant are required to be calculated.