Environmental Engineering Reference
In-Depth Information
Hot air flows with high
velocity through the chimney
Solar
chimney
Collector
Ambient air
flows under
the collector
Air under the collector heated up by
solar irradiance flows upwards to the chimney
Wind turbine
Figure 1.13
Principle of the Solar Chimney Power Plant
best efficiency of solar chimney power plants is currently below 2 per cent. It
depends mainly on the height of the tower. Due to the large area required,
these power plants can only be constructed on cheap or free land. Suitable
areas could be situated in desert regions. However, the whole power plant has
additional benefits, as the outer area under the collector roof can also be
utilized as a greenhouse for agricultural purposes. As with trough and tower
plants, the minimum economic size of a solar chimney power plant is in the
multi-megawatt range. Figure 1.13 illustrates the principle of the solar chimney
power plant.
Solar thermal power plants typically have poor part-load behaviour and
should be installed in regions with a minimum of around 2000 full-load hours
in Earth's sunbelt. However, thermal storage can increase the number of full-
load hours significantly. The specific system costs are between
2000/kW and
€
5000/kW depending on the system size, system concept and storage size.
Hence, a 50-MW solar thermal power plant will cost
€
100-250 million. At
good sites, today's solar thermal power plants can generate electricity at
around
€
0.15/kWh. Series production could soon bring down these costs to
€
below
0.10/kWh. The potential for solar thermal power plants is enormous:
for instance, about 1 per cent of the area of the Sahara desert covered with
solar thermal power plants would theoretically be sufficient to meet the entire
global electricity demand. Therefore, it is highly probable, as well as desirable,
that solar thermal power systems will play an important role in the world's
future electricity supply.
€
Solar collectors for water heating
Solar thermal energy can not only be used
for the production of high-temperature heat and electricity but also for
covering the demand for low-temperature heat for room heating or domestic
water heating. Solar collector systems are currently used mainly for domestic
water heating and swimming pool heating, but they have rarely been used for
room heating systems until now.
