1. “CHARACTERIZATION OF CONCENTRATED LIGHT BEAMS WITH APPLICATIONS TO
International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006
“CHARACTERIZATION OF CONCENTRATED LIGHT BEAMS WITH APPLICATIONS TO
SOLAR CONCENTRATORS”
Part B:
“Radiometric methods”
Antonio Parretta
ENEA – Bologna

2. OUTLINE 1. The Double Cavity Radiometer: i) Theory
ii) Practical realization
iii) Calibration
iv) Applications
2. Introduction to radiometers for solar concentrators with cylindrical receivers
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

3. DCR-1 Radiometer Optical fibre
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

4. DCR-1 Radiometer
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

5. DCR-1 Radiometer Solar Simulator Gauge head Diode array Spectrograph
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

6. DCR-1 Radiometer
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

7. DCR-1 Radiometer Spectrum of light Control module
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

8. DCR-1 Radiometer Touchscreen of the control module
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

9. DOUBLE-CAVITY RADIOMETER (DCR)
Calibration
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

10. DCR Calibration at PASAN Solar Simulator
Lamp power
supply
Console
simulator + PC
DCR
Radiometer
T (°C)
I/V
dia lf sc la bo co ra cr sl
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

11. DCR Calibration at PASAN Solar Simulator
DCR gauge head
Fresnel lens
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

12. DCR Calibration
Calibration curves obtained by pulsed measurements of Isc on the DCR
and on the reference SP-HECO252 cell.
Measurements taken at T=25°C. Input window area: Sin= 1.96 cm2.

13. Reflectance of DCR wall
Reflectance of DCR internal wall as function of wavelength.

14. Attenuation factor for power measurements
Experimental attenuation factor vs. insert area, compared to
the curves of the optical model. Added dark area = 0 cm2.

15. Attenuation factor for power measurements
Experimental attenuation factor vs. insert area, compared to
the curves of the optical model. Added dark area = 1 cm2.

16. Attenuation factor for flux density measurements
Experimental data of attenuation factor vs. insert area, compared to
the curves of the analytical optical model. Added dark area = 1 cm2.

17. CONCLUSIONS ABOUT DCR
The DCR radiometer is a simple and easy-to-use apparatus.
Main features of DCR:
i) It measures both the total power of the beam and the flux density distribution.
ii) It allows the controlled and precise attenuation of the incident radiation.
It can operate between about 1 sun up to thousands of suns.
iv) The response is quite independent of the incident direction and divergence of the beam.
The measurement is made in a stationary regime.
ACKNOWLEDGEMENTS to M. Pellegrino, G. Flaminio (ENEA-Portici) for the PASAN calibration measurements.
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

18. RADIOMETERS FOR SOLAR CONCENTRATORS WITH CYLINDRICAL RECEIVERS
Introduction
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

19. Photovoltaic collar (1st version)
Eleven Photodetectors: HECO 252 SunPower cells
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

20. Photovoltaic collar (2nd version)
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

21. Photovoltaic collar (2nd version)
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

22. Photovoltaic collar (2nd version)
Photo taken by a CCD from the bottom of the mirrors
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

23. Photovoltaic collar (2nd version)
Corresponding photodetectors signals
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

24. Photovoltaic collar (2nd version)
Photodetectors temperatures
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006

25. CONCLUSIONS ABOUT PV COLLAR
A static PV collar has been developed
It allows to obtain precise measurements of concentrated radiation
Temperature of photodetectors is acceptably low
Ways to select the incoming radiation are being studied
A moving version of the PV collar is under project
Optical calibration with PASAN at Portici for absolute measurements are foreseen
Ist International School on Concentrated Photovoltaics, Ferrara 2-6 September 2006