Performance of a parabolic trough solar collector

Authors

  • M J Brooks Department of Mechanical Engineering, Mangosuthu Technikon
  • I Mills Department of Mechanical Engineering, Mangosuthu Technikon
  • T M Harms Department of Mechanical Engineering, University of Stellenbosch

DOI:

https://doi.org/10.17159/2413-3051/2006/v17i3a3291

Keywords:

parabolic trough collector, time constant, acceptance angle, optical efficiency

Abstract

The performance of a South African parabolic trough solar collector (PTSC) module has been characterised using the ASHRAE 93-1986 standard. The collector is designed for component testing and development in a solar energy research programme. Low-temperature testing was performed at Mangosuthu Technikon’s STARlab facility using water as the working fluid. Both an evacuated glassshielded receiver and an unshielded receiver were tested, with which peak thermal efficiencies of 53.8% and 55.2% were obtained respectively. The glass-shielded element offered superior performance at the maximum test temperature, desensitising the receiver to wind and reducing the overall heat loss coefficient by half. The collector time constants for both receivers indicate low thermal inertia and the measured acceptance angles exceed the tracking accuracy of the PTSC, ensuring the collector operates within 2% of its optimal efficiency at all times. Off-sun thermal loss results and the behaviour of the PTSC under increased angles of incidence are described. A description of the test system components is given.

Downloads

Download data is not yet available.

References

ASHRAE (American Society of Heating, Refrigerating

and Air-Conditioning Engineers) 1991. Methods of

testing to determine the thermal performance of solar

collectors. ANSI/ASHRAE 93-1986 (RA 91).

Bakos, G. C., Adamopoulos, D., Soursos, M. and Tsagas,

N. F. 1999. Design and construction of a line-focus

parabolic trough solar concentrator for electricity generation.

In Proceedings of ISES Solar World

Congress, Jerusalem.

Blanco-Muriel, M., Alarcón-Padilla D. C., LópezMoratalla

T. & Lara-Coira M. 2001. Computing the

solar vector. Solar Energy 70 (5): 431-441.

Brooks, M. J. 2005. Performance of a parabolic trough

solar collector, M Sc (Eng) thesis. University of

Stellenbosch.

Cleveland, T. 2005. Description and performance of a

TRNSYS model of the Solargenix Tracking Power

Roof. In Proceedings of ISES Solar World Congress,

Orlando.

Dudley, V. E., Evans, L. R. & Matthews, C. W. 1995. Test

results: Industrial Solar Technology parabolic trough

solar collector. SAND94-1117. Sandia National

Laboratories.

Duffie, J. A. & Beckman, W. A. 1991. Solar engineering

of thermal processes, John Wiley & Sons, Inc.

Geyer, M., Lüpfert, E., Osuna, R., Esteban, A., Schiel, W.,

Schweitzer, A., Zarza, E., Nava, P., Langenkamp, J. &

Mandelberg E. 2002. EuroTrough – Parabolic trough

collector developed for cost efficient solar power generation.

Paper presented at the 11th Int. Symposium

on Concentrating Solar Power and Chemical Energy

Technologies, Zurich.

Ibrahim, S. M. A. 1996. The forced circulation performance

of a sun tracking parabolic concentrator collector.

In Proceedings of the World Renewable Energy

Congress, Denver.

Kalogirou, S. 1996. Parabolic trough collector system for

low temperature steam generation: design and performance

characteristics. Applied Energy 55: 1-19.

Lamprecht A. J. 2000. Efficiency improvement of parabolic

trough solar collector, Mechanical Project 478.

University of Stellenbosch.

Naidoo, P. 2005. Intelligent control and tracking of a solar

parabolic trough. DTech dissertation. Nelson Mandela

Metropolitan University. In preparation.

National Renewable Energy Laboratory. 2004. Heating

water with solar energy costs less at the Phoenix

Federal Correctional Institution, DOE/GO-102004-

Stine, W. B. & Harrigan, R. W. 1985. Solar energy fundamentals

and design with computer applications,

John Wiley & Sons, Inc.

Downloads

Published

2006-08-01

How to Cite

Performance of a parabolic trough solar collector. (2006). Journal of Energy in Southern Africa, 17(3), 71-80. https://doi.org/10.17159/2413-3051/2006/v17i3a3291