Environmental Engineering Reference
In-Depth Information
This section will focus on the applications of TES in concentrating solar power
plants and building and industrial process heat and seasonal heating.
Concentrating Solar Power Applications
Perhaps the most pertinent application of TES is in large scale concentrat-
ing solar power (CSP) plants. CSP technologies use mirrors to reflect and
concentrate sunlight onto receivers in a solar field that collect the energy and
convert it to heat. One advantage of parabolic trough CSPs is their potential
for storing solar thermal energy to use during nonsolar periods and dis-
patch it when most needed. TES allows parabolic trough power plants to
achieve higher annual capacity factors—from 25% without thermal storage
up to 70% or more with it. The heat from the concentrated radiation is used
to increase the temperature of a working heat transfer fluid to approximately
400°C and carries energy to a steam generation unit, like the ones shown in
Figures 7.11 and 7.12.
Figure 7.11 illustrates a concentrating solar power plant that utilizes two-
tank indirect TES. The expansion of steam through the turbine produces
mechanical torque for electric generation [6]. The steam cycle next undergoes
condensation and heat rejection before recycling to gain heat from exchange
with the absorber heat transfer fluid [6]. This vapor power production is
described by a four-step Rankine cycle and is shown in Figure 7.12 [6]. The
Rankine cycle involves (1) isentropic compression of water by a pump, (2) con-
stant pressure heat addition in the steam generator, (3) isentropic expansion
Steam Turbine
Solar Field
G
Solar
Reheater
Co
n
denser
Hot Salt Tank
Solar
Superheater
Steam
Generator
Cooling Tower
Water Supply
Detector
Cold Salt Tank
Solar
Preheater
Expansion Vessel
FIGURE 7.11
Diagram of Abengoa Solar's Solana power plant in Gila Bend, Arizona. (From Abengoa Solar:
Our Projects. Solana. http://www.abengoasolar.com/corp/web/en/our_projects/solana/
index.html. With permission.)
