Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Modelling and simulation of a Linear Fresnel CPVT system
Submission Author:
Darío Gerardo Fantini , DF
Co-Authors:
Pedro Neto, Darío Gerardo Fantini, Mario Benjamim Baptista de Siqueira
Presenter: Mario Benjamim Baptista de Siqueira
doi://10.26678/ABCM.COBEM2023.COB2023-1761
Abstract
This work aims to develop the mathematical modelling of a linear Fresnel CPVT (Concentration Photovoltaic Thermal) system to simulate its dynamic behaviour under real conditions of ambient temperature, irradiance, and wind speed in the facilities of the Energy and Environment Laboratory of the University of Brasilia. The modelling is based on a linear Fresnel solar concentrator 4 m wide by 4 m long, 19 mirrors with dimensions of 4 m long and 0.2 m wide with south-north orientation in the longitudinal direction of the mirrors. Besides the concentrator, there is a heat absorber module composed of a 2m by 0.125m duct, in which the lateral and superior faces are thermally insulated, and the inferior face has the photovoltaic cells that receive the luminous flux generated by the concentrator. Water flows through the duct to cool the cells so that they work at a temperature below 90°C with irradiance values above 5000W/m2. The relevance of this model lies in the methodology used that integrates the optical model of the concentrator (considering the non-uniformity of the illumination and making use of the free software TONATIUH) and the model of the photovoltaic cell (at the point of maximum power and considering the existence of deviation diodes) within the thermal system of the heat absorber. To model the thermal system of the absorber, the energy balance is performed in each of the finite volumes considered within its geometry and then the system of equations is solved using the Newton-Raphson method. In the simulation of the CPVT system model with real input data (irradiance, ambient temperature, and wind speed) with a fluid mass flow rate inside the absorber duct of 0.01kg/s, for the mentioned place, considering the non-uniformity of irradiance in the receiver and the deviation diodes in the cells, an electrical efficiency of 7.32% and a thermal efficiency of 45.22% is achieved. The model presented 100% of convergence for both constant and variable input data and allowed the determination of the thermal transient of the system for different flow rates.
Keywords
Linear Fresnel CPVT system, Concentration Photovoltaic Thermal, Simulation CPVT, Modelling CPVT
