No abstract

No abstract

No abstract

No abstract

No abstract

No abstract

The combined CaCO 3 -calcination and CH 4 -reforming process is investigated using concentrated solar energy as the source of high-temperature process heat. The thermodynamic equilibrium composition indicates the coproduction of lime and syngas (H 2 /CO molar ratio = 1) at above 1200 K and 1 bar. Exploratory experimental runs were carried out with a 5 kW solar chemical reactor comprised of a windowed cavity-receiver containing a flow of CH 4 with suspended CaCO 3 particles and directly exposed to high-flux solar radiation. At an optimal reactor configuration, CaCO 3 and CH 4 conversions of 83% and 38%, respectively, were achieved during 11 min of irradiation at a solar concentration ratio of 1884 suns and a nominal temperature of 1223 K. Effecting simultaneously both reactions in a single solar-driven reactor eliminates CO 2 emissions derived from the separate fossil-fuel-based production of these two energy-intensive material commodities.

Improving mechanical system efficiency is the goal of many engineers and scientists. Commonly, the solutions to these types of problems are uncovered using thermodynamic analysis and optimization. An innovative method for the thermodynamic analysis of a complex energy-intensive system with an arbitrary structure is described in this paper. The method is based on a novel general equation to calculate the total system exergy efficiency using an exergy flow graph proposed by the authors. Discuss in this paper exergy efficiency and exergy loss models as well this approach allows a user to obtain not only the exergy losses and efficiency of the total system, but also to show the relationship between the exergy efficiency of an individual element and that of the entire system. An example is provided that employs this method to the thermodynamic analysis of an air refrigerator.