Solar collector is one of the solar energy technologies that has been used in the world. This simple device like flat plate solar collector can convert the solar energy into heat energy. However, solar collector’s efficiency is directly depended upon the solar radiation intensity falling on its surface. In order to increase the solar concentration over the collector, side reflectors are introduced which will concentrate both diffuse and direct radiations from the sun toward the collector surface. Other method introduced to enhance the collector performance was curved header tube having four times the diameter of header tube that is 100mm to avoid shadow effect and the corrugated absorber plate having a radius of 27mm to give better heat transfer between the plate and riser tube with double glazing arrangements to reduce top loss heat transfer coefficient. The experiment was carried out for four days from 10:00 to 15:00 hrs by thermosiphon principle in two season late rainy season and the second set during the dry season in climatic condition of Bahir Dar, Ethiopia. The experimental result shows that the average output temperature and efficiency for day one, two, three and four was 76.5℃ ��� 73.3%, 73.8℃ ��� 73.7%, 87.02℃ ��� 77.6%, and 88.25℃ ��� 78.9%, respectively. Additionally, the maximum collector output temperature and efficiency was recorded on day four that is 92℃ ��� 82.12℃ at 14:30hr. Regarding to the double glass cover the average maximum temperature between first glass to second glass cover and between first glass to absorber plate was 134.13℃ ��� 152.4℃, respectively. From these testing days the overall average collector output temperature and efficiency was 81.5℃ ��� 75.9%, respectively. The effect of reflector on the performance of the collector analytically modeled and validated to experimental measurement. It was found that the optimum angle for higher solar radiation was the angle inclined between the left side reflector and the collector (� 1 ) varies between 36.8° ��� 68.5° for calculated result, 35.1° ��� 69.5° for experimental measurement. On the other hand, the angle inclined between the right side reflector and the collector (� 2 ) varies between 43.2° ��� 75.3° for calculated result, 44.1° ��� 76.3° for experimental measurement. Finally, all result compared to other literatures and clearly observed that the present work has best performance enhancement. Key words: solar concentration, curved header tube, reflector, corrugated plate,