Maximally concentrating optics for photovoltaic solar energy conversion. Technical progress report, [July 1, 1985--February 15, 1986]
The use of a two-stage concentrator with a fresnel lens primary and a non-imaging dielectric totally internally reflecting secondary, has unique advantages for photovoltaic concentration. This new design has a much larger acceptance angle than the conventional lens-cell concentrating system. In the continuation of this research, an optimally designed prototype which employs a 13.6-cm diameter flat fresnel tons as the primary focusing device, a dielectric compound hyperbolic concentrator (DCHC) as secondary and a 1-cm diameter high-concentration cell for electricity conversion has been built, tested and analyzed. Measurements under sunlight show that it has an angular acceptance of {plus_minus}3.6 degrees, which is dramatically better than the {plus_minus}0.5 degree achievable without a secondary concentrator. This performance agrees well with theoretical ray-tracing predictions. The secondary shows an optical efficiency of (91{plus_minus}2)% at normal incidence. Combining with the primary fresnel tens which has an optical efficiency of (82{plus_minus}2)%, tho two-stage system yields a total optical efficiency of (7l{plus_minus}2)%. The measurement of the system electrical performance yielded a net electrical efficiency of 11.9%. No problems associated with non-uniform cell illumination were found, as evidenced by the excellent fill factor of (79{plus_minus}2)% measured under concentration. The secondary geometrical properties and the optimal two-stage design procedures for various primary- cell combinations were systematical studied. A general design principle has been developed.
- Research Organization:
- Chicago Univ., IL (United States). Enrico Fermi Inst.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-84CH10201
- OSTI ID:
- 10182423
- Report Number(s):
- DOE/CH/10201-T4; ON: DE93002845
- Resource Relation:
- Other Information: PBD: 27 Feb 1986
- Country of Publication:
- United States
- Language:
- English
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Maximally concentrating optics for photovoltaic solar energy conversion. Technical progress report, [July 1, 1984--January 31, 1985]
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