Simultaneous Multiple Surface method for Linear Fresnel concentrators with tubular receiver

Abstract

Linear Fresnel concentrators (LFR) are known for their potential cost-effectiveness, reliability and wide range of possible solar applications. However, this technology is still facing the challenge of increasing its overall performance, especially in the Concentrated Solar Power (CSP) field where Parabolic Trough and Central Tower Receiver concentrators are the predominant solutions. In order to increase the performance of conventional LFR concentrators it is necessary to increase their optical performance as these concentrators are still far from the theoretical limits of concentration. This paper presents a new Fresnel concentrator designed with the Simultaneous Multiple Surface (SMS) method for two reflective (X) surfaces (Fresnel XX SMS) and with a tubular receiver. This design also promotes a good light uniformity on the receiver. A comparison is made between this new Fresnel XX SMS and two present day available concentrators (a Fresnel with CPC (Compound Parabolic Concentrator) and a PT (Parabolic Trough) concentrator), as well as a calculation of the total amount of collected energy (kW h), before thermal losses, for a particular location, Faro (Portugal). Furthermore, a new definition of CAP (Concentration Acceptance Product) is proposed, as the standard definition does not fully take into account the optical nature of LFR concentrators. The paper ends with a discussion of the results obtained, their impact and possible applications in the future.