First experimental results, conclusions and further steps
A solar concentrator with a fixed reflector has been developed. The first prototype of the collector consists in a 4.5 x 6 m reflector that concentrates the sun radiation on 8 rows of evacuated tubes (Fig. 12).
The experimental characterization of the collector is still under progress. By now the highest efficiency obtained for an inlet temperature of 100°C is 43% for a direct incident radiation of 890
 |
W/m2. Although this thermal efficiency is low compared to the 70% of maximum optical efficiency obtained for normal incidence, it should be taken into account that it has been obtained for an incidence angle close to, but not coincident, with the normal, that the reflector was not cleaned, and that in the evaluation of the optical efficiency, structure shadows and edge effects were not taken into account. Therefore there is still room to optimize the design in order to approach to the theoretical limits, particularly in the areas of the upper structure design and the fine adjustment of the tracking. In the next months it is planed to further evaluate the collector under different radiation and weather conditions and to numerically simulate a detailed collector model using ray-tracing techniques. This will allow the identification of the primary sources of losses and will provide the fundamental guidelines to optimize the prototype.
This project has been funded by the CIDEM, an agency of the Generalitat de Catalunya (regional
government from Catalonia), and by a PROFIT credit of the Spanish Ministry of Industry, Tourism and
Commerce.
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[6] Russell, J. L, Jr. Principles of the fixed mirror concentrator. General Atomic Company. San Diego, California. SPIE Vol. 85 Optics in Solar Energy Utilization. 1976.
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[8] Pujol R. Analisis de un concentrador solar lineal con reflector fijo y foco movil siguiendo una trayectoria circular. A final paper presented for the degree of Master of Physics. Universitat de les Illes Balears. September 1974.
[9] Martinez V. Pujol R., Moia A. Schwiger H. Analysis of a stationary parabolic linear concentrator with tracking absorber. 13th International Symposium on concentrating solar power and chemical energy technology. 2006.
