Experimental investigation of the direct absorption receiver concept

Abstract

This paper describes the results of an experimental analysis of a flowing-film liquid direct absorption receiver (DAR) concept. Results of a numerical model of the thermal performance are also included. Experiments were conducted with concentrated solar flux at the Advanced Components Test Facility (ACTF) in Atlanta, Ga. Data are presented that support analysis of the film stability at high and low flow rates, thermal efficiency, and heat transfer (between the salt and the absorber plate). Comparisons of the data with analytical predictions of thermal efficiency and heat transfer were favorable and suggest a thermal efficiency of 80–90%, depending on operating temperature and flux. Heat transfer coefficients (for the undoped salt) of about 3000 W/m 2 °C were observed. No flow instabilities at high flow rates (Reynolds number up to 1200) were observed; however, a dry-out problem for flow rates below that was observed, which may be caused by experimental artifacts.