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The objective of the study was to evaluate diverse and known types of heat transfer fluids (water, oil and glycerin) commonly used in solar thermal systems, in this work denoted as base fluids, with respect to them, but with the addition of biosynthesized metal nanoparticles. It was considered a prototype of solar heating systems by thermosiphon in the application-experimental phase assisted by halogen light (with wavelengths ranging from deep infrared to violet). The process of biosynthesis or green synthesis of silver nanoparticles (NP Ag) was from the precursor of silver nitrate (AgNO3) and using as a reducer the alcoholic extract from agroindustrial residues of the wine production, obtaining colloids with high monodispersity and with sizes between 30 and 40 nm. (spherical geometry). The results suggest a greater increase in heat absorption capacity when biosynthesized silver nanoparticles are added to the oil, which managed to have a heat capacity of 3519.41 J/kg°C.

With the passing of time, the demand for dehydrated organic products has increased, ranging from vegetables to fruits, however in the latter efforts to achieve a quality product have led to the use of industrialized systems which depend on the use of fossil fuels or systems that use electric current which greatly increase production costs. At present, various solar dryer models have emerged, having achieved an optimal performance in what corresponds to the processing of vegetables, however in the processes of dehydration of fruits the results have not been satisfactory, due to the loss of its color, taste, aroma and texture (organoleptic properties). Faced with this problem, an innovative design of solar fruit dehydrator is proposed, which has two objectives, the first related to recovering the organoleptic properties through a system of condenzation, cyclic dehydration and the synchronization of the calorific balance, and the second one focused on the improvement of thermal efficiency, through the use of some heat piles and a trombe wall. The heat transfer fluid was improved, adding silver nanoparticles (silver nanospheres), which were synthesized using the green chemistry method; the efficiency of the heat transfer fluid was increased by 30%.