Heat transfer within linear Fresnel unit using parabolic reflector

Abstract

Purpose

This paper scrutinizes exergy loss and hydrothermal analysis of Linear Fresnel Reflector (LFR) unit by means of FLUENT. Several mirrors were used to guide the solar radiation inside the receiver, which has parabolic shape. Radiation model was used to simulate radiation mode.

Design/methodology/approach

Heat losses from receiver should be minimized to reach the optimized design. Outputs were summarized as contours of incident radiation, isotherm and streamline. Outputs were classified in terms of contours and plots to depict the influence of temperature of hot wall, wind velocity and configurations on performance of Linear Fresnel Reflector (LFR) based on thermal and exergy treatment. Four arrangements for LFR units are considered and all of them have same height.

Findings

Greatest Nu and E_x can be obtained for case D due to the highest heat loss from hot wall. Share of radiative heat flux relative to total heat flux is about 94% for case D. In case D when T_r = 0.388, As h_ext rises from 5 to 20, Nu_total enhances about 11.42% when T_r = 0.388. By selecting case D instead of case A, E_x rises about 16.14% for lowest T_r. Nu_total and E_x of case D augment by 3.65 and 6.23 times with rise of T_r when h_ext = 5. To evaluate the thermal performance (η_th) of system, absorber pipe was inserted below the parabolic reflector and 12 mirrors were used above the ground. The outputs revealed that η_th decreases about 14.31% and 2.54% with augment of T_in and Q if other factors are minimum.

Originality value

This paper scrutinizes exergy loss and hydrothermal analysis of LFR unit by means of finite volume method. Several mirror used to guide the solar radiation inside the receiver, which has parabolic shape. DO model was used to simulate radiation mode. Heat losses from receiver should be minimized to reach the optimized design. Outputs were summarized as contours of incident radiation, isotherm and streamline.

Citation

Ebrahimpour, Z., Farshad, S.A. and Sheikholeslami, M. (2022), "Heat transfer within linear Fresnel unit using parabolic reflector", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 32 No. 8, pp. 2841-2863. https://doi.org/10.1108/HFF-05-2021-0338