Unlike the power generation of photovoltaic and wind power plants, which are subject to natural fluctuations, solar thermal power plants are controllable and can thus stabilize the climate-neutral energy systems of the future. GEFRAN's pressure transmitters are suitable for monitoring the liquid salt heat accumulator in the power plant circuit, and they thus ensure the efficient operation of the plants.
In solar thermal power plants, a molten salt stores heat generated by solar power. This allows the plant to produce steam even at night, which then drives a turbine, which in turn is coupled to a generator. Here, the kinetic energy is converted into electricity.
GEFRAN pressure transmitter
However, efficient operation of a solar thermal power plant is only possible when the molten salt has an optimal consistency. The liquid begins to solidify when its temperature falls below 270 °C. From a temperature of <250 °C, the melt turns into a ceramic block.
This undesirable process can be prevented by using GEFRAN pressure transmitters. The KE SIL2 high-temperature pressure sensors measure media pressures in environments with temperatures of up to 538 °C (1000 °F) at the diaphragm and can thus detect even the smallest changes in the liquid heat accumulator.
The pressure is detected by a hydraulic system consisting of a capillary with an inner diameter of 0.1 mm. This contains a non-compressible transmission fluid (NaK, sodium/potassium), which transfers the pressure of the hot molten salt to a measuring membrane. There, a strain gauge converts the physical quantity "pressure" into an electrical signal that is sent to the higher-level plant control system.
High temperature pressure sensors
The KE SIL2 high-temperature pressure sensors offer measuring ranges from 0..17 to 0..1000 bar or 0..250 to 0..15000 psi and have a very low signal noise of < 0.025 percent of the final value. They have an autozero function and can also invalidate the variation of the pressure signal caused by the variation of the ground temperature by an automatic internal compensation. Since the KE SIL2 has SIL2 certification (IEC/EN 62061/ IEC 61508), it can also be used in applications with high functional safety requirements. The sensors have a current output of 4...20 mA and feature reverse polarity and short circuit protection as well as a compensated temperature range of 0 ...+85 °C.