Profit and efficiency enhancement of a cylindrical solar collector by structural modification of helical tube

Abstract

Cylindrical solar collectors (CSCs) are getting attraction. Heat extraction part of these instruments consists of a helical tube which transfers thermal energy to working fluid. Enhancement of the heat transfer process within this part leads to enhancement of energy achievement. In this paper, influence of applying helical corrugation on helical absorber was evaluated. The number of corrugations and pitch and height of corrugations were considered as variant parameters. The system was evaluated from different viewpoints and performance of system was analyzed based on performance factor and economic viewpoints. The results revealed that the presence of helical Corrugation could increase heat transfer up to 19%. It was found that Dean number of 3000 could be considered as a critical Dean number from view point of performance factor. The application of the proposed system was more beneficial at Dean numbers below 3000. It was revealed that the application of helical corrugation could provide up to 24% enhancement in economic advantage of the system. Best economic performance was related to case with four starts which had corrugation height and corrugation pitch of 0.002 m and 0.103 m and occurred at Dean number of 2000.