Development of a Novel Concept of Solar Receiver/Thermal Energy Storage System Based on Compartmented Dense Gas Fluidized Beds

The development of a novel concept of Concentrated Solar Power (CSP) generation system featuring thermal energy storage is addressed. The system is based on a compartmented dense gas fluidized bed. A dynamical model of the system laid the basis for optimizing collection of incident radiative power, heat transfer to the steam cycle, storage of energy as sensible heat of bed solids. It provided the ground for the basic design of a 100kWth demonstration CSP plant. INTRODUCTION Development and deployment of Concentrated Solar Power (CSP) generation is gaining renewed interest. The US Department of Energy has launched the SunShot program [1] targeted at reducing the LCOE from CSP to less than 6cent/kWh. The European Commission has laid the path to CSP development and deployment in the Framework Programmes and in the forthcoming SET plan [2]. A survey by IEA has recently analyzed priorities and opportunities associated with CSP [3], highlighting the key role of integrated thermal energy storage (TES) and fuel-power hybridization for the successful exploitation of concentrated solar power. The potential of gas-solid fluidized beds (or more generally of gas-solid suspensions) as useful components in CSP has been recognized. The use of fluidized solids as alternative to other storage/exchange media, like molten salts, entails the possibility to overcome issues associated with the use of corrosive or environmentally unfriendly fluids and to operate the receiver at much higher temperature (with associated improved overall efficiency of the energy conversion cycle). Fluidized bed solar receivers have been investigated at the proof-of-concept or lab-scale levels [4-12], but full exploitation at the demonstration scale is still missing. A research consortium has been established by the Magaldi industrial group, the University of Naples and the National Research Council of Italy with the goal of developing a novel concept of solar receiver for CHP (combined heat and power) generation featuring thermal energy storage. The basic concept is the development of a Solar Generation Unit (SGU) consisting of a compartmented dense gas fluidized bed (Fig. 1) optimized so as to accomplish the following three complementary tasks: Collection: Effective collection of incident solar radiation in a beam-down concentrated solar power arrangement is targeted at limiting re-emission of the incident radiation and at minimizing local overheating at the surface of the receiver exposed to densely concentrated incident radiation. re ce iv er ex ch an ge st or ag e incident radiation