Persona: D Souza, David Jonathan
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D Souza
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David Jonathan
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Publicación Proposal of a new design of central solar receiver for pressurised gases and supercritical fluids(Elsevier, 2023-07-10) Guedez Mata, Rafael; Linares Hurtado, José Ignacio; González Aguilar, José; Romero, Manuel; Montes Pita, María José; D Souza, David JonathanThis work presents a novel design of microchannel central receiver for pressurised gases and supercritical fluids in solar tower plants. It consists of a radial arrangement of vertical absorber panels that converge on the central axis of the tower. The absorber panels comprise compact structures, whose compactness is increased in one flow pass compared to the previous one, as the fluid is heated. This concept reduces radiation heat losses due to its light-trapping geometry and increases heat transfer to the thermal fluid without over penalising its pressure drop. For the receiver assessment, it has been developed a thermal resistance model characterising the fluid heating along the panel height and the temperature gradient between parallel channel rows of the compact structure across the panel thickness. Once the thermal and optical boundary conditions are defined, an optimisation analysis of the main geometrical parameters of the receiver has been accomplished. The receiver performance is evaluated by means of a global exergy efficiency referred to the solar subsystem, which computes the receiver heat losses, the fluid pressure drop and the optical efficiency of the heliostat field in which the receiver is integrated. For each parametric optimisation, the configuration that maximises this efficiency is identified.Publicación Experimental assessment of different compact flow channel geometries on pressurised gas solar receivers(Elsevier, 2025-01-19) D Souza, David Jonathan; Montes Pita, María José; Romero, Manuel; González Aguilar, José; Comunidad de Madrid (CAM)Pressurised gas receivers using optimised compact flow channels exhibit promising thermal performance in concentrated solar thermal systems, paving the way to integrate solar energy in high efficiency thermodynamic power cycles and industrial heat processes. This work is focused on the experimental characterisation of several compact absorber samples, in order to verify previous numerical analysis aimed at maximising thermal efficiency while simultaneously minimising pressure drop. Four variants of plain rectangular channel absorber samples were fabricated varying channel height, breadth and wall thickness. Each absorber sample was experimentally studied by varying mass flow rate, inlet pressure and incident radiation flux. The experimental campaign verified important findings and predictions of a previously developed numerical model including that the maximum thermal efficiency and pressure drop occurs at the smallest channel size besides the positive effect of taller and narrower channels. The maximum thermal efficiency observed was 95.8% with the corresponding pressure drop measured at 6.3% of the inlet pressure. This performance, in terms of thermal efficiency and relative pressure drops, is on par and even surpasses the state-of-the-art receivers of its type. Such high thermal efficiencies (above 90%) and low relative pressure drops (below 3%) were also observed for other operating conditions and absorber geometries as well.Publicación Application of compact flow channel geometries to pressurised solar receivers: a numerical and experimental analysis(Universidad Nacional de Educación a Distancia (España). Escuela Internacional de Doctorado. Programa de Doctorado en Tecnologías Industriales, 2023) D Souza, David Jonathan; Montes Pita, María José; González Aguilar, José; Romero Álvarez, ManuelPublicación Energy and exergy analysis of microchannel central solar receivers for pressurised fluids(Elsevier, 2023-01-25) Romero, Manuel; González Aguilar, José; Montes Pita, María José; D Souza, David JonathanWithin the new generation of advanced central solar receivers, microchannel pressurised gas receivers are emerging as reliable and efficient alternatives to operate at high temperatures and pressures. This paper presents an optimisation and comparative analysis of different compact plate-fin type structures, constituting the receiver’s absorber panels, classified according to the type of fin arrangement inside: plain rectangular, plain triangular, wavy, offset strip, perforated, and louvred fin. A versatile thermo-fluid receiver model is implemented, allowing simple variation of characteristic geometric parameters of each structure. Exergy efficiency is chosen as the optimisation function, as it considers both heat and pressure losses. The framework of the analysis is set by the receiver’s boundary conditions, operating at the design point conditions of a solar thermal power plant. For each compact structure, the optimal configuration is determined, providing interesting findings that have not been reported in the state-of-the-art to date. Although all geometries show good thermal performance, the perforated and plain rectangular configurations demonstrate the best exergy efficiencies of 59.21% and 58.80%, respectively, favouring taller and narrower channels. This analysis methodology could be seamlessly extrapolated to other gases and working conditions, owing to the thermo-fluid model’s versatility, to reveal the optimal configuration for each case.