Novel heat-transfer medium and air wall build up performance of sun thermal tower energy crops

The upper the receiver temperature, the extra successfully a sun thermal energy plant will perform. Convective thermal losses even have the most important impact on yield. The HelioGLOW collaborative challenge by way of Fraunhofer Institute for Sun Power Programs ISE and commercial companions is operating to deal with those demanding situations: The challenge workforce investigated a unique ceramic heat-transfer medium together with energy plant design and air wall for the thermal insulation of the receiver. The fashion towards ceaselessly bettering manufacturing processes is mirrored within the construction of the Stellio heliostat.

The result of the challenge are offered within the just lately revealed ultimate record (in German).

Standard sun tower energy crops paintings with molten salt as a heat-transfer medium, which imposes a temperature prohibit: Above 600°C, the corrosiveness of the salt will reason harm. The HelioGLOW challenge works with a solid-state heat-transfer medium, which permits for an running temperature of greater than 1,000°C, significantly boosting performance.

The warmth-transfer medium is pushed even though the receiver thru a bespoke procedure paying homage to a carousel, and heated up right away. To this finish, Kraftblock GmbH evolved novel ceramic receiver components manufactured from non-corrosive, environmentally pleasant subject matter with a excessive warmth garage capability. The ceramic subject matter is produced in a recycling procedure, which makes it cost-efficient.

The fabric’s temperature construction and balance had been characterised at a Fraunhofer ISE check stand, adopted by way of exams within the sun simulator on the IMDEA Power Institute in Madrid. The challenge workforce was once ready to make use of the measuring effects as a foundation for inspecting the fabric’s habits beneath excessive sun radiation. “The following function can be to additional expand the receiver’s subject matter to permit the power to be transmitted deeper into the frame,” explains Dr.-Ing. Gregor Bern, Team Supervisor Concentrating programs and applied sciences at Fraunhofer ISE.

The radical solid-state receiver combines radiation receiver, heat-transfer medium and garage subject matter, decreasing the prices for energy plant development. Warmth move resistance and boundaries of flux density like in typical tube receivers are eradicated. The ensuing upper temperature, which will also be maintained higher even if sun radiation is fluctuating, additionally give a contribution to decreasing the prices of sun thermal electrical energy technology.

Air wall reduces thermal loss by way of 30%

Solar energy towers normally face convective thermal losses, which scale back the performance when the temperature is excessive and sun irradiation has a excessive focus. Whilst the air temperature at the receiver can move as much as 600°C, the temperature of the ambient air is in most cases round 30°C to 40°C. Warmth from the receiver is transferred to the cooler air because it flows previous it. A separation of various air volumes will also be completed by way of quartz glass panes, which aren’t to be had within the required dimension, alternatively.

To triumph over this downside, Fraunhofer ISE examined the speculation of an “air wall” generated by way of robust nozzles at the receiver’s opening to split the air volumes.

“Till just lately, there had simplest been simulations for this answer, however the era had by no means been demonstrated in a real energy plant,” explains Moritz Bitterling, analysis affiliate within the Fraunhofer ISE challenge workforce.

An ordinary dimension check setup provided with ca. 50 temperature sensors was once used to simulate a receiver at 600°C the usage of heating components. Our commercial spouse, Luftwandtechnik GmbH, designed an air wall gadget particularly for high-temperature programs and put in it on the receiver check stand at Fraunhofer ISE in Freiburg. The use of this setup, convective thermal losses with an air wall had been when compared with the ones with out an air wall, measuring the heating energy important to reach 600°C. The right running parameters, akin to the attitude of the air wall nozzles and the air outflow pace had been agreed with Luftwandtechnik GmbH. The receiver’s convective thermal losses may well be decreased by way of 30%. This era could also be appropriate for different industries operating with high-temperature processes, the place the separation of main temperature variations on furnaces and so on. can scale back losses. The challenge companions are making plans to check this in follow-up initiatives.

Additional construction of heliostats and full energy crops

The place sun thermal electrical energy technology is worried, there’s a pattern against smaller solar energy towers. This is the reason, within the HelioGLOW challenge, Fraunhofer ISE and sbp sonne GmbH are operating on additional growing their Stellio heliostat. The function was once an optimized pylon design and the difference of the design to the necessities of smaller solar energy towers so as to additional scale back prices. Fraunhofer ISE used 3-D laser scanning to measure the heliostat’s parameters and examined processes for speedy heliostat measurements within the box. Deflectometric measurements of the reflector surfaces within the laboratory was once used to research the deformation results beneath particular load eventualities.

The workforce at Fraunhofer ISE then evolved an general idea in keeping with the entire parts discussed above, integrating the solid-state heat-transfer medium receiver, the air wall and the optimized Stellio heliostat right into a sun thermal energy plant. The researchers evaluated which energy plant procedure is most fitted for coupling and the way the warmth will also be transferred from the solid-state subject matter to the facility plant procedure. The full gadget was once modeled, tested and its technical and financial efficiency was once evaluated the usage of the thermo-hydraulic simulation software ColSim CSP. This was once ready to amplify at the current technical-economic fashions and establish the perfect format and operation for an influence plant with the brand new parts.