Evaluation of the coupling of Linear Fresnel Reflectors to a refrigerator operating on a diffusion-absorption cycle

• Mathematical modelling of an unconventional solar refrigeration system. • Thermal reservoir operated under unsteady-state • Fluid heated via LFR can replace electricity. • Full system operation with higher solar incidence. • Energy losses of the system were found significant. The bubble generation and pumping system (generator) of commercial refrigerators, which operate on a diffusion and absorption cycle, is typically powered by electricity, rendering it unusable in locations without access to an electrical grid. An alternative to this process is the coupling of a concentric tube heat exchanger, with heated thermal fluid circulating through the annular space. Therefore, the objective of this work is to investigate this coupling, considering the heating of the thermal fluid in a concentrating collector such as Linear Fresnel Reflectors (LFR) and its storage in a stratified thermal reservoir. Mathematical models for predicting the performance of each subsystem available in the literature were used to construct a model for predicting the performance of the entire system. For this, the models of the LFR and the thermal reservoir were validated using experimental data found in the literature. The system's performance was evaluated using Brazilian solarimetric conditions, considering its operation in the cities of Fortaleza and Bauru, which are cities at different latitudes, over a period of 48 hours, starting on representative days of the months with the highest (November for Fortaleza, December for Bauru) and lowest (April for Fortaleza, June for Bauru radiation incidence. It was found that the system in question can operate fully on the representative days of the months with the highest radiation incidence. Furthermore, the daily energy balance of the system showed that losses in the generator section are significant, and under certain operating conditions, it would be necessary to use an alternative energy source for heating (e.g., biomethane or biomass burning), despite the proper functioning of the system.