pressurized hot water circuit with a field of 5065 m² of Abengoa PT-1 collectors operates at a temperature of up to
250°C and pressure reaching 41 bar, heating a steam generator that produces 21 bar steam for the plant steam line
[7].
To avoid investing in a steam generator and to reduce thermal capacities resulting in long start-up times, DSG
processes have been developed, as demonstrated in the P3 project [3] depicted below (Figure 5). To produce
saturated steam, liquid water enters the solar field, is heated up to the boiling point, and starts evaporating. To avoid
overheating and mechanical stress on the absorbers the control system must ensure that a portion of liquid water
remains in the flow to cool the absorbers, resulting in a water-steam mixture leaving the solar field. This design still
requires a steam drum to fulfill two functions: separation of steam from liquid water and compensation of water
content fluctuations in the solar field and piping. The water content changes when the solar field starts generating
steam in the morning, since the steam displaces liquid water in most of the collector and in the piping between solar
field and boiler.
Figure 5: