A prototype 4 kW solar thermochemical reactor for the continuous splitting of carbon dioxide via the isothermal ceria redox cycle is demonstrated. These first tests of the new reactor showcase both the innovation of continuous on-sun fuel production in a single reactor and remarkably effective heat recovery of the sensible heat of the reactant and product gases. The impact of selection of gas flow rates is explored with respect to reactor fuel productivity and external energy costs of gas separation and pumping. Thermal impacts of gas flow selection are explored by coupling measured temperatures with a computational fluid dynamics (CFD) model to calculate internal temperature distributions and estimate heat recovery. Optimized gas flows selected for operation provide a 75% increase in fuel productivity and reduction in parasitic energy costs by 10% with respect to the design case.

The structural and thermal feasibility of a self-supporting sandwich panel for energy efficient residential roof applications is assessed. The assessment is limited to symmetric sandwich panels comprising two face sheets and an insulating core. Feasible panel designs are presented for loading conditions, corresponding to southern and northern climates in the United States. The base case panel is 5.5m long for a nominal 4.6m horizontal span and an 8∕12 roof pitch. Face sheet materials considered are oriented strand board, steel, and fiber reinforced plastic. Core materials considered are expanded polystyrene, extruded polystyrene, polyurethane, and poly(vinyl-chloride) foams. A wide range of material options meet building code limits on deflection and weight and prevent face sheet fracture and buckling, and core shear failure. Panels are identified that have structural depths similar to conventional wood rafter construction. Shortening the overall panel length provides greater choice in the use of materials and decreases the required panel thickness. Suggestions for improved panel designs address uncertainty in the ability of the plastic core to withstand long term loading over the expected life of residential buildings.

The structural and thermal feasibility of a self-supporting sandwich panel for energy efficient residential roof applications is assessed. The assessment is limited to symmetric sandwich panels comprising two face sheets and an insulating core. Feasible panel designs are presented for loading conditions, corresponding to southern and northern climates in the United States. The base case panel is 5.5 m long for a nominal 4.6 m horizontal span and an 8/12 roof pitch. Face sheet materials considered are oriented strand board, steel, and fiber reinforced plastic. Core materials considered are expanded polystyrene, extruded polystyrene, polyurethane and poly(vinyl-chloride) foams. A wide range of material options meet building code limits on deflection and weight and prevent face sheet fracture and buckling, and core shear failure. Panels are identified that have structural depths similar to conventional wood rafter construction. Shortening the overall panel length provides greater choice in the use of materials and decreases the required panel thickness. Suggestions for improved panel designs address uncertainty in the ability of the plastic core to withstand long term loading over the expected life of residential buildings.

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