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This paper presents modeling, simulation and analysis of heat transfer and fluid flow in the tapered receiver used in solar cycloidal concentrating system which is a novel concept. The main objective of this paper is to analyze performance of solar cycloidal concentrating system by utilizing novel concept of tapered receiver for enhancement of system efficiency. This solar cycloidal concentrating system is used for testing purpose from Jan 20-April 20 in Pune city, India. The calibrated device Pyranometer is used to provide values of solar irradiance. Readings are taken daily after each one hour for the whole day. Modeling of the tapered receiver tube which is novelty of this research is done using SOLIDWORKS software. The governing equations of fluid flow and heat transfer in the system are solved by using ANSYS-CFX CFD software. The obtained results show efficiency increment and rise in temperature. Experimental results and analysis using software shows that using novel concept of tapered receiver, there is noticeable decrement in thermal losses as there is decrement in the area of receiver from inlet to outlet of receiver tube and hence increase in the efficiency is observed. The tapered receiver is designed in such a way that, the entire receiver tube of 20 feet is cut into a separate 20 pieces. Each piece is having 304.80 mm in long. Total 20 pieces are separately designed for manufacturing of taper receiver. For each piece cut of 0.9 mm from inlet to outlet is taken for OD as well as for ID using CNC machine. Tapered receiver was manufactured by using various operations which includes MS rod cutting, machining, welding, arrangement for sensor fitting at said location and end nozzles.

In this paper, the design and development of a solar cycloidal concentrating system along with utilization of the tapered receiver is presented. For the determination of the performance of the system, theoretical analysis was carried out. The novel concept of utilizing a tapered receiver for a solar cycloidal concentrating system is an innovative approach for this research. After the determination of various parameters for this system, a patent was filed and published under the patent No. 202021028009A on 31 July 2020. For the comparative study purpose, the author has taken three receivers with a constant concentration ratio and different diameters such as .038 m, .031 m, and .025 m. Theoretical evaluation of the system is estimated using modes of heat transfers and using the relation of energy balance. Various correlations are determined for an analytical evaluation purpose. By using graphical collation of all the results for all the three receivers, the author has proposed to use a tapered receiver with the variable CR. CR denotes the concentration ratio. A concentration ratio is defined as the ratio of the area of an aperture to the area of a receiver. In this research, a variable concentration ratio (CR) is used. The receiver used has a diameter which reduces from the inlet to the outlet, and hence, the intercept factor decreases and the concentration ratio increases, leading to an enhancement in efficiency.

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The present line concentrator system with constant concentration ratio exhibits rise in temperature of working media, however if the difference between outlet and inlet temperature of working media is large then they exhibit lower efficiency. Also the rate of fall of efficiency with increase in its temperature difference is high. To overcome this problem it is proposed to have a variable concentration ratio concentrator system. The variable concentration ratio is achieved by employing receiver consisting of the pipes having different diameters; with the larger diameter pipe at start followed by small diameter receiver. Thus, the concentrator system will have different diameter receivers offering variable concentration ratio system. This concept is confirmed with the help of G.O. Lof, Fester and Duffie Beck paper. The present paper describes above concept by graphical analysis carried out for the newly proposed circular line concentrator with variable concentration ratio. The results of superimposition of graphs leads to confirmation for the promisingly use of variable concentration ratio receivers for enhancing efficiency of solar concentrating system.