EFFECT OF PARABOLIC TROUGH SOLAR COLLECTOR ORIENTATION ON ITS COLLECTION EFFICIENCY

摘要

Parabolic trough solar collector PTC is often oriented with its axis horizontally in the North-South or East-West direction. However, it may be set in a position where its axis makes an angle P with the south direction. The main objective of the present work is to study the effect of this angle on the collection efficiency. An algorithm for calculating the collection efficiency for any time period has been developed. The results obtained by using this algorithm show that the maximum daily collection efficiencies rc d all over the year are obtained for the N-S orientation at sites having latitude angles 15. For latitude angles φ≤15°, are much higher in summer days than in winter ones for N-S orientation. In the case of orienting the collector with an angle 70°<Ψ≤, 90°, are higher in winter days than in summer ones This orientation is preferable to obtain almost constant output of PTC through the whole year. The results show also that a trough oriented with an angle of 70° from N-S direction has almost a constant daily collection efficiency all over the year in order of 82% when considering the reflectivity of the collector surface equal to unity. Also, the effect of orientation on yearly collection efficiency T|c are minor at latitude angle between 30°and 40° while the effect of orientation becomes important outside this range.