The control of solar processes requires the control of solar illumination and temperatures.
The particularities of solar furnaces – very high temperatures, parasitic solar reflections, concentrated fluxes, optical pyrometry – require specific means of measurement.
Dans ce sens, le laboratoire PROMES possède une expérience In this sense, the PROMES laboratory has significant experience in the following areas
- Concentrated solar flux measurement,
- Pyrometry blind to solar radiation,
- Study of solidification points in the range 2000-3000°C,
- Optical pyrometry: calibration and methods adapted to the determination of the real temperature for ‘in situ’ conditions.
All these activities are grouped in the alliance of European laboratories working in the solar field: SOLLAB.
MEANS OF MEASURING THE CONCENTRATED SOLAR FLUX
- Water calorimeter : Absolute measurement, Name: Double sheet, Measuring range <20000 kW/s, Inlet diaphragm: 10mm, Shape: Cylinder, Coating: Black C, Temperature sensors: Thermocouples, Water flow measurement: Coriolis, Response time: 10s, Opening angle: 2×60°.
- Water calorimeter : Absolute measurement, Name: Asterix, Measuring range <20000 kW/s, Inlet diaphragm: 3mm, Shape: cylinder, Coating: paint, Temperature sensors: thermocouples, Water flow measurement: water weight measurement, Response time: 10s, Opening angle: 2×60°.
- Radiometer : relative measurement (calibration required), Name: integrating sphere calorimeter, Measuring range: 1 to 20000 kW/s, Input aperture: 3mm, Shape: sphere, Coating: paint, Sensor: Si. photodiode, Response time: 0.001s, Opening angle: 2×60°, Accuracy: 5%.
- Imaging : relative measurement (calibration required)
SUNBLIND PYROMETERS
- 1-Name: Impac, Detector: InGaS , Wavelength: 1.4µm , Response time: 0.01s , Optics: Lenses and fiber optics, Focal length: 0.6 m, Spot: 3mm.
- 2- Name: Heiman, Detector: Bolometer , Wavelength: interchangeable, Response time: 0.1s , Optics: Cassegrain, Focal length: 1.3m, Spot: 7mm.
- 3-Name : Heitronic, Detector: Pyroelectric , Wavelength: interchangeable, Response time: 0.1s , Optics: lenses, Focal length: 1m , Spot: 6 mm
- 4-Name : Heitronic, Detector: Pyroelectric , Wavelength: 5.1µm, Response time: 0.1s , Optics: lenses, Focal length: 0.5m, Spot: 3mm
- 5-Name: Ircon, Detector: Pyroelectric, Wavelength: 5.2µm, Response time: 0.1s, Optics: lenses, Focal length: 1.2m, Spot: 6mm
- 6-Infrared camera, Optics: lenses, Wavelength: 5µm.
MEASUREMENT OF SOLIDIFICATION POINTS
Solar furnaces allow to easily obtain uncontaminated molten auto-crystals. The device used and an example of a crucible are presented below. .
MEANS OF CALIBRATION OF PYROMETERS AND PYROREFLECTOMETERS
For accuracy, the calibration of the pyrometers of the laboratory are regularly controlled by comparison on industrial black bodies with a standard pyrometer:
- 1-Name: Pyrox (LaCr2O3 ), Max Temperature:1700°C, Atmosphere: Air .
- 2-Name: Micron, Max Temperature:1200°C, Atmosphere: Air, Equipped with diaphragms
- 3-Name: Pyrox (Graphite), Max Temperature: 2600°C, Atmosphere: Inert.
The determination of the actual temperature of opaque materials for ‘in situ’ conditions is performed with pyroreflectometers equipped with fiber optic probes.