Experimental performance of a two-stage (50X) parabolic trough collector tested to 650 °C using a suspended particulate (alumina) HTF. (15th July 2018)

• Record Type: Journal Article
• Authors: Widyolar, Bennett; Jiang, Lun; Ferry, Jonathan; Winston, Roland
• Is Part Of: Applied energy. Volume 222(2018)
• Page Start: 228
• Page End: 243
• Publication Date: 2018-07-15
• Subjects: Solar thermal -- Industrial process heat -- Parabolic trough -- Compound parabolic concentrator -- Nonimaging optics -- Alumina -- Particles; CSP concentrated solar power -- HTF heat transfer fluid -- PV photovoltaic -- TES thermal energy storage -- PTC parabolic trough collector -- CPC compound parabolic concentrator -- UCM University of California, Merced -- TC thermocouple -- HCE heat collecting element -- NIP normal incidence pyrheliometer -- HX heat exchanger; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2018.03.173
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: Two-stage optics generate 50X geometric concentration on thermal absorber. Experimental testing performed with particulate alumina heat transfer fluid. Deformation of secondary reflector resolved through passive cooling. Prototype demonstrates 63% optical efficiency, 40% efficiency at 650 °C. Abstract: A two-stage high-concentration collector is designed which pairs a 45° half rim angle parabolic trough with a compound parabolic concentrator (CPC) secondary to achieve 50X concentration on the thermal absorber. An experimental prototype fabricated & installed at the University of California in Merced is tested on-sun up to 650 °C using a suspended particulate (alumina) heat transfer fluid (HTF). Early deformation of the secondary reflector was fixed by implementing a passive cooling technique. The prototype collector demonstrates 63% optical efficiency and 40% thermal efficiency at 650 °C and pathways towards improving both optical and thermal efficiency have been identified. Obstacles encountered during testing are discussed, which highlight the need for further investigation into the heat transfer mechanisms within the fluidized particulate stream. This prototype demonstrates the feasibility of the two-stage linear trough collector at generating high flux, high temperatures, and the ability of the particulate alumina HTF to operate under these conditions.