Annual Report 2006 - Plataforma Solar de Almería

FACILITIES AND INSTALLATIONS
Figure 2.2 General diagram of the stationary solar collector test platform
system provides the MED plant with the thermal energy required for its operation.
The solar field is composed of 252 stationary solar collectors (CPC Ao
Sol 1.12x) with a total surface area of 500 m 2 , arranged in four rows of 63
collectors. The maximum working temperature is 100ºC since the collectors
are connected to atmospheric pressure storage tanks in an open loop. The
thermal storage system consists of two water tanks connected to each other
for a total storage capacity of 24 m 3 . This volume allows the operation sufficient
autonomy for the backup system to reach nominal operating conditions.
The double effect (LiBr-H 2 O) absorption heat pump is connected to the last
effect of the MED plant. The low-pressure saturated steam (35ºC, 56 mbar)
produced in this cell supplies the heat pump evaporator with thermal energy,
which would otherwise be discharged to the atmosphere, cutting in half the
thermal energy consumption required by a conventional multi-effect distillation
process. The fossil backup system is a propane water-tube boiler with a
10-bar saturated steam production capacity of 200 kg/h. This boiler ensures
heat pump operating conditions (180ºC, 10 bar), as well as operating the
MED plant in the absence of solar radiation.
2.9 Stationary Solar Collector Test Platform
This facility was built in 2002 for the purpose of offering additional services
to the scientific research community, among which was the possibility of carrying
out energy characterization of the stationary solar collectors, with special
emphasis on its possible application to solar desalination processes.
The facility has three independent hydraulic circuits. In the primary fluid
circuit (water or water mixed with antifreeze) is heated as it flows through the
solar collector, delivering the energy acquired to the water deposited in a
storage tank. In the secondary circuit, the water from the tank is pumped to
the heat exchanger where its energy is transferred to the tertiary circuit. This
heat exchanger simulates the hot water inlet in the first cell of a multi-effect
distillation plant. Finally, the water that circulating through the tertiary circuit
toes to a cooling tower where the energy from the secondary circuit is discharged
into the atmosphere.
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