Abstract
The performance of an advanced corrugated duct solar collector was contrasted with that of five conventional collector designs under the climatic conditions of Cairo, Egypt. Efficiency of the corrugated duct system increased by a ratio of 15-43% relative to that of the flow-below flat absorber, representing the next best conventional design. Use of transparent rectangular slats in the air gap, with an aspect ratio of 2.0, enhanced efficiency by 34% relative to that for the same collector without slats.