The state of Sonora, Mexico, stands as one of the leading producers of pecan nuts in the country, which are commercialized without shells, leaving behind this unused residue. Additionally, this region has abundant solar resources, as shown by its high levels of direct normal irradiance (DNI). This study contributes to research efforts aimed at achieving a synergy between concentrated solar energy technology and biomass pyrolysis processes, with the idea of using the advantages of organic waste to reduce greenhouse gas emissions and avoiding the combustion of conventional pyrolysis through the concentration of solar thermal energy. The objective of this study is to pioneer a new experimental analysis methodology in research on solar pyrolysis reactors. The two main features of this new methodology are, firstly, the comparison of temperature profiles during the heating of inert and reactive materials and, secondly, the analysis of heating rates. This facilitated a better interpretation of the observed phenomenon. The methodology encompasses two different thermal experiments: (A) the pyrolysis of pecan shells and (B) the heating–cooling process of the biochar produced in experiment (A). Additionally, an experiment involving the heating of volcanic stone is presented, which reveals the temperature profiles of an inert material and serves as a comparative reference with experiment (B). In this experimental study, 50 g of pecan shells were subjected to pyrolysis within a cylindrical stainless-steel reactor with a volume of 156 cm³, heated by concentrated radiation from a solar simulator. Three different heat fluxes were applied (234, 482, and 725 W), resulting in maximum reaction temperatures of 382, 498, and 674 °C, respectively. Pyrolysis gas analyses (H₂, CO, CO₂, and CH₄) and characterization of the obtained biochar were conducted. The analysis of heating rates, both for biochar heating and biomass pyrolysis, facilitated the identification, differentiation, and interpretation of processes such as moisture evaporation, tar production endpoint, cellulosic material pyrolysis, and lignin degradation. This analysis proved to be a valuable tool as it revealed heating and cooling patterns that were not previously identified. The potential implications of this tool would be associated with improvements in the design and operation protocols of solar reactors.

The use of concentrated solar energy in processing ceramic materials is an attractive route to obtain these materials with low CO₂ emissions. In this work, nanostructures of monoclinic zirconia (m-ZrO₂) were obtained using concentrated solar energy provided by the IER-UNAM solar furnace as a heat source. In the first stage of the process, a Zr/O/C complex was obtained by sol-gel method at a temperature of 120 °C using zirconium n-propoxide and sorbitol as precursors reagents. This complex was used in a second stage to obtain m-ZrO₂ by heating it at a temperature of 1200 °C for one hour in air atmosphere. This last stage was performed in a solar furnace. Samples were analyzed by characterization techniques: FT-IR, TGA/DSC, XRD, TEM, and SEM confirming the formation of nanostructures of zirconia in monoclinic phase.

Copper is an indispensable input element in most economic sectors. However, its production chain has significant and adverse consequences on the environment. Through pyrometallurgical route it is estimated that each kilogram of refined copper consumes 33 MJ and generates a footprint of 3.3 kg of CO₂. Primary production projections for 2019 amount to 26,500 kT, of which 79% will be by pyrometallurgical route. It is a responsibility of the industry to makes the process more environmental friendly. This can be done replacing the current energy matrix by the use of renewable energy. In this first and preliminary work we are evaluating the technical potential to integrate Central Tower Plants (CTP) into the smelting stage as a solar energy source. According to the mineral books and the irradiation maps, almost 20% of the current production can be match with these solar concentration systems because of the irradiance levels available where the metallurgical plants are located. The incorporation of a CTP in the world largest copper metallurgical facility to substitute the current fossil fuel energy supply could demand a capacity of 68 MWt. This last consideration obeys to the weighted average of the specific energy consumption gave by the Chilean Copper Commission COCHILCO. However, the results of this work indicate that the behavior of this change in the operative parameters could reduce the 68 MWt almost in a half.

Process heating represents about two-thirds of the energy that the industry sector consumes worldwide; this energy comes primarily from burning fossil fuels. There is a wide variety of processes for which solar technologies can supply energy. Within these technologies, the CSP_th Central Tower produces heat at temperatures about 600 °C, making it suitable for high-temperature processes. A CSP_th Central Tower can be combined with a fuel-based system to form a CSP_th Hybrid Central Tower system, which results in a high-reliable energy source with low rates of CO₂ emissions. In this work, the levelized cost of heat (LCOH) of the CSP_th Hybrid Central Tower technology was calculated. SolarPILOT was used to design and evaluate the CSP_th Central Tower; fuel consumption was calculated using a steady-state energy balance. The LCOH was evaluated considering the CO₂ prices recommended by the High-Level Commission on Carbon Pricing. The analysis shows that this technology can be highly competitive and, in certain cases, shows lower LCOH than fuel-based systems. However, these cases depend on reasonable CO₂ prices, low costs of capital (≈5%), and efforts to reduce the capital expenditure, which can nowadays be possible for CSP_th Hybrid Central Tower systems designed with large solar multiples.

Tracking the apparent movement of the sun with high precision is crucial in dual-axis tracking systems for solar concentration applications. It is important to develop control strategies to reduce losses by solar radiation displacement (drift) on the receiver and improve the solar concentration system. In concentrated photovoltaics, a high-precision tracking control is required to keep the concentration point. This paper compares open-loop and closed-loop solar tracking control strategies to solve drift problems and correct azimuth and elevation angles in a non-image reflective FRESNEL solar concentrator. The open-loop strategy consists of a programming code to calculate the apparent sun position, sending command signals to the actuator systems in azimuth and elevation tracker axes. In the open-loop strategy, the actual position of the sun is not verified. A closed-loop strategy with a visual monitoring device is proposed here to detect the sun’s position in real time. This can be simultaneously compared with a fixed reference to evaluate drift through time, calculate the generated error, and send feedback signals to correct azimuth and elevation angles. With this configuration, displacement containment of the solar point concentration projection was ±0.00215 m in the azimuth direction and ±0.0027 m in the elevation direction on the receiver.