Environmental Engineering Reference
In-Depth Information
$52.5M/11 MW
$4.77/W. This report (http://ec.europa.eu/energy/res/sectors/
doc/csp/ps10_
nal_report.pdf.) makes it clear that the location was optimum (see
also Figure 1.7a) both from the point of view of available sunlight and from the point
of view of the cost of land.
This type of installation can be improved to reach its potential high ef
ciency with
high technology in the heat collector and heat
uid and turbine design. An example of
a smaller but higher performance system is shown in Figure 5.5. A higher operating
temperature is available in a closed cycle Stirling engine using helium or hydrogen
gas, with no need for a heat
fluid transport. In a Stirling engine, the same limited
volume of gas cycles back and forth in a repetitive fashion.
A report of
g
L
¼
P
electric
/
P
s
ef
ciency in a separate Stirling engine system
(https://share.sandia.gov/news/resources/releases/2008/solargrid.html.) indicates
that a substantially higher collector temperature is available in Stirling engines. The
reported dish had 82 mirrors focused on a 7 in. aperture of the hydrogen-based
Stirling engine. The 31% efficiency was demonstrated as electric power output
divided by solar energy input, and the record was set on a cold day such that the
presumably air-cooled cold port of the Stirling engine could be maintained at
23
C
¼
¼
0.31
296 K. Over a period of several hours during the day, the dish system
maintained an electrical output 26.5 kW or about 36 hp. A substantial exhaust heat
¼
Figure 5.5 EuroDISH parabolic mirror Stirling
engine on tracking platform developed by
Plataforma Solar de Almeria (PSA) in Spain. A
closed cycle of hydrogen or helium gas in the
compact Stirling engine unit allows a higher
collector temperature, increasing the efficiency
to 30%. This is a self-sufficient power source
that might be used in a rural location,
augmented by electrical storage in batteries or
by electrolytically produced hydrogen from
water, that could be used on demand to run fuel
cells (http://en.wikipedia.org/wiki/File:
EuroDishSBP_front.jpg.).
