Analysis of Concentrating Solar Thermal System to Support Thermochemical Energy Storage or Solar Fuel Generation Processes

Abstract

A Concentrating solar thermal (CST) system integrated with a high-performance solar receiver can provide high-temperature process heat to drive thermochemical energy storage (TCES) or thermochemical fuel production processes with improved equilibrium conversion and fast reaction rates. An advantage of integrating a CST system with a thermochemical process is the ability to store chemical energy in large quantities for continuous downstream operations. However, a challenge in the effective conversion of solar energy to power or fuels is that high-temperature thermochemical process operating conditions require a high solar concentration ratio for efficient operation which imposes design difficulties for solar energy collection. Integration of the solar collection system with a thermochemical process affects the system efficiency and final product cost due to the relatively high solar field cost. Thus, optimization of the collection system provides a significant opportunity to reduce cost of solar thermochemical power or fuel. In this paper, we present a solar field layout strategy and assess the feasibility of a novel planar-cavity receiver to drive thermochemical processes with reaction temperatures in the range of 500–900°C. The complete solar collection system performance is examined and importance of conducting coupled field/receiver analyses is demonstrated by illustrating how improved spillage control by a modified heliostat aiming strategy impacts system radiative losses downstream. The planar-cavity receiver shows improved performance with increasing concentration ratio and superior performance over a flat plate receiver operating under the same prescribed operating conditions.