Solar-pumped solid-state lasers are promising for renewable extreme-temperature material processing. Here, we report a significant improvement in solar laser collection efficiency by pumping the most widely used Nd:YAG single-crystal rod through a heliostat-parabolic mirror system. A conical-shaped fused silica light guide with 3D-CPC output end is used to both transmit and compress the concentrated solar radiation from the focal zone of a 2 m diameter parabolic mirror to a 5 mm diameter Nd:YAG rod within a conical pump cavity, which enables multi-pass pumping through the laser rod. 40 W cw laser power is measured, corresponding to 13.9 W m −2 record-high collection efficiency for the solar laser pumped through a heliostat-parabolic mirror system. 2.9% slope efficiency is fitted, corresponding to 132% enhancement over that of our previous pumping scheme. 209% reduction in threshold pump power is also registered.
Global solar radiation data is essential in the design of solar energy conversion devices. The most widely used model in the estimation of the global solar radiation coming to the earth's surface is the Angtröm-Prescott model. In this model, relative sunshine duration plays an important role. In the current study, it was attempted to review different models and to determine the best performing model developed for the city of Bechar and two locations of Algerian Big South desert for solar energy projects and compare them with the different established models available in the literature up until now, based on measured sunshine hours data. The new models give high accuracies on the application, where (R 2) ranges between 0.70 and 0.99. In addition, MBE and RMSE values are very low in the studied stations. The results presented in this paper are quite useful for quick estimation of global solar radiation data required for performance evaluation of solar collector used for different applications of solar energy.
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