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Linear Fresnel collectors are becoming an attractive option to generate electricity from solar radiation. This paper is focused in the thermal performance of Fresnel collectors working with different heat transfer fluids: synthetic oil, water-steam, molten salt and air, also comparing the results of the Fresnel technology with those obtained in reference parabolic trough loops. Although there are two basic designs of the Fresnel receiver: multi-tube and single-tube with secondary concentrator, this work only studies in depth the single-tube option, as this design is more suitable for a proper comparison with parabolic troughs. The receiver in parabolic troughs has been modeled as an evacuated tube with a selective coating and a glass cover. For Fresnel receivers it has been simulated two different configurations: non-evacuated receiver, with a glass window at the cavity aperture and evacuated receiver, characterized by a tube with a glass cover and a selective coating.

We have investigated the hydrodynamic response of plastic and aluminum foils accelerated by a pulse formed by an x‐ray prepulse followed by the main laser pulse. This illumination scheme, so‐called indirect‐direct drive scheme, has been proposed as an alternative to the direct and indirect drive. The advantages of such a scheme are that it can contribute to solve the problem of uniformity of the direct drive and, at the same time, it can be much more efficient and use simpler targets than the indirect‐drive. Experiments about this hybrid drive scheme have been performed at Limeil with the PHEBUS facility and the standard experimental set‐up and diagnostics. The agreement between experiments and simulations is good for quantities such as the energy of the laser converted into x‐rays and the burnthrough time of the converter foil. To simulate the full hydrodynamic evolution of the converter and target foils separated a distance of 1 mm, 2‐D effects should be taken into account. The basic goals have been to ...

An X‐ray prepulse followed by a laser pulse is proposed for a direct‐indirect drive scheme in the inertial confinement fusion. A numerical simulation of the hydrodynamic efficiency of acceleration is performed for an aluminium foil. The dual pulses are useful for the thermal smoothness. (AIP)

Ignition models for Inertial Confinement Fusion (ICF) are analyzed on the basis of fuel energy balances. Spark ignition models are in general identified as more effective alternatives than raw volume ignition. Nevertheless, it is demonstrated that volume ignition can yield very high energy gains comparable to spark ignition if the whole picture is properly taken into account. References are made to some outstanding experiments and to numerical simulations which support this tutorial explanation.