1 Low Cost Concentrator Solar ArrayIAC-16.C2.8.9x33920 Collette J.P. Walopt, Belgium, Rochus P., Hodgetts P., Nutal N., Larnicol M., Crahay J., Kloos T., Nols Ph. September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

2 Presentation overviewIntroduction V-Trough concept Improved temperature management Reflector wrinkles measurement Measurement of optical performance with wrinkles Numerical simulation of optical performance Conclusions Acknowledgment September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

3 Introduction Primary target of concentration = surface gain for the solar cells. First interest of a high concentration ratio (70’s and 80’s). But pointing and thermal design issues !  Some Fresnel concentrator still survive with a moderate concentration ratio of C < 10.  In the 90’s, low concentration appeared (C < 2.5), easily adapted to classical panels. Commercial spacecrafts in early 2000: gradual loss of power due to various causes. September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

4 Attention was paid to the contamination of the reflectors and operational temperature. A Multi-V design has been developed by the author. Recently, JAXA launched its small REIMEI scientific spacecraft, with two solar arrays equipped with a single lateral reflector. September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

5 Reimei satellite with two wings and half concentrators Fukuda, SReimei satellite with two wings and half concentrators Fukuda, S. & et al. (2006) September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

6 V trough design limits NRL, 1998September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

7 Improved Temperature ManagementDevelopment of an improved low cost reflector Temperature field of a full solar panel with reflectors September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

8 Eclipse on the solar panel and reflector T reflector always > T panel September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

9 Wrinkles by shear stressReflectors wrinkles Wrinkles by shear stress September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

10 Measurement of wrinkles3D scanner calibration set-up September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

11 3D scanner view of wrinklesSeptember Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

12 Color scan uni-axial tensionSeptember Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

13 Color scan bi-axial tension stateSeptember Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

14 Measurement of optical performanceOptical bench September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

15 Solar cell with flat rigid mirrorSeptember Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

16 Solar cell with wrinkles on the mirrorSeptember Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

17 measurement of the reflected light (wrinkles) with a photodiodeSeptember Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

18 Simulation of wrinkles effectsNumerical model of wrinkles September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

19 Simulation of solar irradiance on the panel with wrinkles Simulation Measurements September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

20 Conclusions The effects of wrinkles on the reflector are well understood and a simulation tool has been developed and qualified to extrapolate the results to a full scale. The thermal behavior of the solar generator has been improved. The developments of a low cost concentrator are still going on at the time being. A laboratory model will be manufactured at a reduced scale (about A4). September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt

21 Acknowledgment This work has been founded by the European Space Agency ESA-ESTEC under contract number /14/NL/EM. The authors wish to thank their colleagues who have made this work possible. September Low Cost Concentrator Solar Array - IAF Guadalajara Walopt