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Concentrating solar power (CSP) is a commercially available renewable energy technology capable of harnessing the immense solar resource in Southern Europe, the Middle East and North Africa (the MENA region), and elsewhere. This paper summarises the findings of a study by the European Academies Science Advisory Council which has examined the current status and development challenges of CSP, and consequently has evaluated the potential contribution of CSP in Europe and the MENA region to 2050. It identifies the actions that will be required by scientists, engineers, policy makers, politicians, business and investors alike, to enable this vast solar resource to make a major contribution to establishing a sustainable energy system. The study concludes that cost reductions of 50-60% in CSP electricity may reasonably be expected in the next 10-15 years, enabling the technology to be cost competitive with fossil-fired power generation at some point between 2020 and 2030. Incorporation of storage delivers added value in enabling CSP to deliver dispatchable power. Incentive schemes will be needed in Europe and MENA countries to enable this point to be achieved. Such schemes should reflect the true value of electricity to the grid, effectively drive R&D, and ensure transparency of performance and cost data.

Abstract: The sewage sludge from San Juan, Argentina, was characterized in an attempt to improve the thermal treatment efficiency and to reduce the environmental impact of incineration. The ash content [...]

Experimental results with a 50 kW solar reactor producing 10-15 g/h single-wall carbon nanotube's rich soot have shown that good quality product was obtained with helium and rather bad product with argon. This result is explained using a computational fluid dynamics model of the reactor accounting for fluid flow, heat transfer, and mass transfer. The bad results in argon were linked to the quenching of carbon vapor in the vaporization zone that resulted in the growth of carbon nanoparticles in spite of carbon-metal clusters (single-wall carbon nanotube precursor). By contrast, the vaporized materials (C, Ni, and Co species) at the target surface were well mixed in helium, and single-wall carbon nanotubes (SWNTs) might grow in the annealing and cooling zone at the backside of the reactor. The same numerical approach may be used to design modifications of the reactor in order to favor the growth of SWNTs. [DOI: 10.1115/1.1949623]

Fullerene mixture of [C.sub.60] and [C.sub.70] was produced in gram quantities in a solar reactor using partially (50 kW) the power of the 1 MW CNRS solar furnace at Odeillo. Fullerene yield was studied as a function of buffer gas (helium and argon), pressure (in the range 80-500 hPa) and gas flow rate. Mean Fullerene yield of 13.5% was measured with helium at 450 hPa and 10 [sm.sup.3]/h, at a carbon vaporization rate of 21 g/h. This mean value refers to three samples collected inside the experimental set up; the maximum yield for one single sample (inside the reactor) was 16%, The dramatic effect of pressure and gas flow rate on the process selectivity is correlated to the dilution number (number of carbon atoms versus number of buffer gas atoms) and to the results of a numerical simulation related to the temperature distribution in the annealing zone of the reactor. Keywords: Solar chemistry, High concentration; Fullerene; Chemical process; High temperature

The two-slab volumetric receiver is theoretically studied and the results are compared with experimental data. Two systems are described; for both of them, slab 2 is composed of SiC particles. Slab 1 is made of glass beads for the first system and silica honeycomb for the second system, the latter being the more efficient. Predicted and measured data show that the efficiency ranges between 70 and 75% for a gas outlet temperature of 1100 K. Predicted results are proved to be very sensitive to slab 1 depth, optical properties, and to the numerical solution of the radiative transfer equation. Band models and a discrete ordinate method are used in this paper. Finally the variation of the receiver efficiency is calculated as a function of slab I scattering albedo; a maximum efficiency of about 90% is reached at 1300 K for albedos in the solar spectrum and the infrared region equal to 0 and 1, respectively.

Analysis of a fluidized bed heat transfer model using exact and simplified approaches for gray and non-gray media reveals that the simplified formulation is valid for large particle beds. The analysis includes solutions to the combined conduction, convection and radiation problem for gray and non-gray media. The radiation transfer rate depends on parameters such as particle size and wall temperature.