The DIAPR: A High-Pressure, High-Temperature Solar Receiver

A solar central receiver absorbs concentrated sunlight and transfers its energy to a working medium (gas, liquid or solid particles), either in a thermal or a thermochemical process. Various attractive high-performance applications require the solar receiver to supply the working fluid at high temperature (900--1,500 C) and high pressure (10--35 bar). As the inner receiver temperature may be well over 1,000 C, sunlight concentration at its aperture must be high (4--8 MW/m{sup 2}), to minimize aperture size and reradiation losses. The Directly Irradiated Annular Pressurized Receiver (DIAPR) is a volumetric (directly irradiated), windowed cavity receiver that operates at aperture flux of up to 10 MW/m{sup 2}. It is capable of supplying hot gas at a pressure of 10--30 bar and exit temperature of up to 1,300 C. The three main innovative components of this receiver are: a Porcupine absorber, made of a high-temperature ceramic (e.g., alumina); a Frustum-Like High-Pressure (FLHIP) window, made of fused silica; a two-stage secondary concentrator followed by the KohinOr light extractor. This paper presents the design principles of the DIAPR, its structure and main components, and examples of experimental and computational results.