The use of solar thermal systems (STSs) has recently reached a significant edge. The increasing research on developing an alternative power supply for limiting fossil fuel usage and climate change are the driving forces of STSs. The current work explores the recent progress in STSs’ applications, including PV/T or “photovoltaic/thermal” systems, zero-energy buildings, greenhouse solar thermal applications, solar thermal for pumping water, solar thermal refrigerators, solar chimneys, water desalination, and solar collectors, along with the benefits and challenges of these applications. Then, the potential contribution of STSs in achieving the various SDGs or “Sustainable development goals”, including barriers and research gaps, are elaborated. In brief, STSs significantly contribute to the seventeen SDGs’ achievement directly and indirectly. Recent developments in the engineering applications of STSs are strongly based on the materials of construction, as well as their design, process optimisation, and integration with multidisciplinary sciences and technologies such as modelling, nanoscience/nanotechnology, and artificial intelligence.

The adsorption of H2 in dehydrated and hydrated Materials of Institute Lavoisier (MIL-101) was investigated theoretically. The effect of terminal water molecules on adsorption as one of the more vital MIL-n trivalent chromium-based porous carboxylates in metal-organic frameworks application in the renewable energy field was also theoretically studied. The MIL-101 structures were optimized for geometry and energy minimization was performed. The calculations were carried out using density functional theory approach with B3LYP functional and mixed basis set of Lanl2DZ and 6-31G(d, p) for Cr and light atoms (C, H, O, F), respectively, as implemented in the Gaussian 09 program package. The spin and atomic charges distribution on the Cr metal atoms, adsorbate, and water molecules are calculated using natural bond orbital (NBO). The density of states (DOS) for the clusters was obtained using Gaussian smearing of Kohn–Sham orbital energies. The natural bond orbital (NBO) for molecular orbital analysis and atomic charge calculations were utilized. For the dehydrated MIL-101, more adsorbate molecules were found near the exposed Cr2 sites than the fluorine saturated Cr1 sites. Furthermore, terminal water molecules in the hydrated MIL-101 made more interaction sites and enhanced adsorption.