Experimental Study of a Helical Coil Receiver Using Fresnel Lens

Abstract

Helical coil cavity receivers have been the object of interest in the past decade for concentrated solar power systems. Fresnel lens is utilized in this study instead of commonly used parabolic dish concentrator owing to its higher optical efficiency and ease of integrating it with the receiver for concentrating the solar radiation at the aperture of the upward-facing open cavity helical receiver. Experimental study is carried out for studying the performance analysis of the helical receiver. The experiments are carried out with compressed air as heat transfer fluid for around 2.5 h about solar noon in Bangalore, India (12.9716{\textdegree} N, 77.5946{\textdegree} E). The variation of efficiency of the receiver during the course of the experiment is studied for three flow rates of 100, 125, and 150 L/min. The maximum air outlet temperature obtained is 164 {\textdegree}C for 100 L/min at 44{\%} efficiency and 140 {\textdegree}C for 150 L/min at 53{\%} efficiency. The effect of direction of flow of heat transfer fluid is also studied, and it is found that higher efficiencies are achieved when the flow is from top to bottom of the receiver. The performance is evaluated based on efficiency and loss coefficient from the receiver.