Design and thermal performance analysis of concentrating solar power tower for water heating systems

With the fossil fuel crisis, the world has been looking for renewable energies, and the concen-trated solar tower (CST) technology has been the best solution in intensive solar areas. This paper introduced a detailed design, construction, and operation of small-scale CST for water heating applications in Aswan. Two heliostats (i.e., 50 x 50 cm2 cross-section area and 1.4 m spacing) redirect the incoming solar radiation into the tower's receiver. The receiver is a 20 x 30 cm2 cross-section area on a 1.0 m tower height and a space of 3.0 m from heliostats. Water flows through a 5.0 cm receiver's passage depth to absorb the reflected energy. This design is obtained from modeling the governing equations of both optical and thermal fields. The designed optical efficiency was X85.46% for the optical field, dominated by the Cosine efficiency. As for the thermal field, a detailed 1-D heat transfer mechanism is presented to predict the internal tem-perature. After construction, an experimental test is done, including temperature measurement of the receiver's outer surface and water inlet/outlet. The result consistently affirmed the mathe-matical model, revealing the CST's ability. Through the designed flowrate of 10.2 L/h and outlet -inlet temperature differences of & UDelta;T = 19.5 & PLUSMN; 0.4OC, the maximum water temperature of X48.5 & PLUSMN; 1.0OC was observed at the daytime of 13:00. The maximum obtained designed efficiency was X52%, showing X19% reduction in the designed values (i.e., optical efficiency was X69.22 & PLUSMN; 8.2%, while receiver efficiency was X74.52 & PLUSMN; 5.4%. This work could provide a prototype to the community, promising advanced application of CST technology in the future.