Civil Engineering Reference
In-Depth Information
FIGURE 9-2
Alternative thermal energy collection technologies.
Desert and is connected to the Southern California Edison's utility grid. This
is more than 90 percent of the world's solar thermal capacity at present.
9.1.2
Central Receiver
In the central receiver system, an array of field mirrors focus the sunlight
on the central receiver mounted on a tower. To focus the sun on the central
receiver at all times, each heliostat is mounted on the dual-axis suntracker
to seek position in the sky that is midway between the receiver and the sun.
Compared to the parabolic trough, this technology produces higher concen-
tration, and hence, higher temperature working medium, usually a salt.
Consequently, it yields higher Carnot efficiency, and is well suited for utility
scale power plants in tens or hundreds of megawatt capacity.
9.1.3
Parabolic Dish
The parabolic dish tracks the sun to focus heat, which drives a sterling heat
engine-generator unit. This technology has applications in relatively small
capacity (tens of kW) due the size of available engines and wind loads on
