Introduction

The invention, result of the joint development with the Magaldi industrial group, of the University of Naples Federico II and CNR, relates to a device for storing and/or exchanging thermal energy of solar origin. The device is based on a fluidized bed of solid particles with direct irradiation of the fluidized granular bed without interposition of means for receiving the concentrated solar radiation.

Technical features

In this novel type of solar receiver the incident solar radiation is concentrated by a system of mirrors in a “solar collector” where the radiative flux invests directly a fluidized suspension of solid particles. The fluidization conditions established in the solar collector entail extended voidage and “volumetric” behaviour of the particle bed so as to warrant very efficient capture of solar radiation. The fluidized solids heated at high temperatures in the solar collector are eventually recirculated to a second fluidized bed in which the heat from the solar source is accumulated or transferred to a heat transfer fluid for thermoelectric generation or to provide process heat. The circulation of the fluidized solid between the “solar collector” and the accumulation / exchange bed occurs through a “loop seal”.

Possible Applications

• Collection, use and storage of concentrated solar radiation for use in thermoelectric generation and/or to provide process heat to applications that require high temperatures, as in the emerging area of “solar chemistry”.

Advantages

• Direct transfer of concentrated solar radiation to the fluidized solids without interposing walls, so that higher temperatures and better heat exchange can be achieved;
• Extended storage of thermal energy at high temperature without resorting to toxic or corrosive substances as storage media;
• Absence of transparent windows, exposed to dulling, fouling and dust deposition phenomena.