The laboratory operates four 2 m and four 1.5 m vertical axis parabolas, part of the eleven Medium Size Solar Furnaces (MSSF).
These parabolas offer great flexibility and great capability to easily host different projects. Their reasonable size, standard equipment and very high performance is tailored for effective innovative processes and material tests with numerous unknown and thus numerous fast needed adaptations.
These concentrators offer either about 1.5 or 1 kW of thermal power at the focus of the 2 and 1.5 m parabolas. The power density is the highest offered by existing solar furnaces: it reaches 16000 kW/m2 at its focus, with a focus diameter about 1.5 and 1 cm wide, allowing temperature in excess of 3800 K - in fact so far no known material withstands these flux under thermal equilibrium without melting... Operation out of focus for greater size and lower power density is easy and accurate thanks to the Z-positioning system.
Each concentrator is indeed fitted with:
- Z-axis motorized and computer controllable positioning support with 0.1 mm precision
- X-Y manual positioning system with clamps for easy position reproducibility
- water circuit for example for cooling
- compressed air for cooling or actuators
- easy access for using high level instrumentation: DAQ, pyrometry, imaging systems, spectrometer...
Several concentrators are equipped with indigenously developed shutters to allow fine control of the power used.
The latest generation being deployed, the Sésame shutters, offers high moving speeds (in standard ~700 ms for 0 to 100 % concentrator's thermal power output, faster possible on request and study) with high accuracy (about 0.5 % repeatability) and very low dead shadow (below 1% of power intercepted). This performance is possible due to the use of modern materials such as carbon based composites and honeycomb and its high power brushless motorizations with state of the art high performance industrial controllers. A brake allows cutting the engine power at any position to allow very low electrical noise operation for fine measurements on the experiment.
The existence of a simple standard 0-10 V analog input allows connection to any regulator, embedded or computer controlled.
For example, the use of a high quality industrial PID regulator has shown surface temperature control with solar-blind pyrometry around 1K on SiC foam between 600 and 1400 K, used either for plateau or programmed thermal cycles.
Such regulators for the energy input can be used to adjust other parameters than a temperature such as a process pressure.