According to the present standards, the optical characterization of line-focusing concentrators follows the quasi-dynamic test method, thus resulting from thermally based experimental measurements. The impact of optical deviations from design conditions on a concentrator optical performance increases with concentration ratio. Adding to this, the geometrical specificities which might be found in line-focus concentrators render important a more thorough optical characterization of such systems.The present article studies the interest and possibility of using optical simulation data as a complement to the experimental procedures followed in the optical characterization of line-focusing concentrators. Taking into account the isolated and combined impact of the most prominent optical effects in presence, the validation and accuracy of optical models is compared to that of experimental measurements. Additional optical characterization results to be obtained from such models are suggested, complementing the optical parameters previewed in the standards and enabling a higher accuracy in yield calculations

Thermal heat transfer fluids (HTF) used in solar collectors (e.g. synthetic oils) are known to age and degrade [1]. This degradation is impossible to control, affecting the fluid heat transfer capacity and thus the ability of measuring the performance of an HTF heating device (e.g. a solar collector) based on known specific heat values.Collector testing is also crucially dependent on an accurate measurement of HTF mass flow rate. Such measurement relies on flow meters suitable for the accuracy, operating temperature and flow range requirements of the testing procedures, often an expensive and demanding component in particular when no-intrusive measurements are to be done ia a close circuit.For power measurement purposes, as those performed in solar collector testing procedures, a direct measurement of the product between specific heat and mass flow rather than a separate measurement of both quantities is suitable. A calorimetric technique delivering this direct measurement is thus a suitable strategy to overcome such difficulties with acceptable (and even higher) measurement accuracy.Solutions of this kind have already been proposed [2,3]. In this paper we revisit and improve the solution presented in [2] and demonstrate its usefulness in a solar collector testing loop, for temperatures up to 200°C. A calorimeter prototype was thoroughly tested and calibrated with water as HTF (enabling accurate independent measurement of specific heat and mass flow rates values). Calorimeter calibration results where then used in the testing with thermal oil whose specific heat values were previously known from manufacturer and independent laboratory measurements.A comparison of Cp measured by the calorimeter with the value given by the HTF manufacturer is used to test the calorimeter capacities. The agreement achieved was very good. It is noted that the technique can be easily implemented in any high temperature loops, large or small

This study provides a comprehensive review of molten salt technology, as well as electrochemical and thermochemical processes aimed at hydrogen and syngas production. First, this research illustrates the current types of molten salt mixtures, detailing their main applications and thermophysical properties. Then, the analysis delves into existing thermo-electrochemical cycles and their specific operating conditions for producing hydrogen and syngas. Moreover, this study assesses the compatibility of these processes with molten salt integration. This investigation involved a comprehensive review of the existing technical and scientific literature, blending insights and practical experiences to offer detailed data on the topics explored. The findings suggest that molten salts, with their medium–high operating temperatures, can markedly improve the efficiency and sustainability of hydrogen and syngas production. Furthermore, this study outlines the pivotal role these technologies can play in achieving the European Union’s ambitious goals by enhancing the use of renewable energy sources and advancing the shift to carbon-free solutions.