Thermal, electrical and structural characteristics under different concentrator positions for Fresnel concentrating photovoltaic system

There are always installation errors in linear Fresnel concentrating photovoltaic (CPV) system that make the system unable to work under the designed conditions. Based on the optical, thermal, electrical, and structural coupling principle, the influences of vertical position (including distance and direction) e of concentrator deviation from the focal length on the thermal (heat flux and temperature distributions), electrical (average electrical efficiency) and structural (stress and deflection) characteristics of PV panel under natural convection conditions were investigated numerically by MCRT-FVM-FEM coupling method. The results reveal that, the thermal, electrical and structural characteristics change slightly with the tilt angle alpha of PV panel from 15 degrees to 60 degrees, while these characteristics experience a relatively greater change for alpha increasing to 75 degrees. The concentrator position has little effect on the flow and temperature fields near the PV panel. Compared with the situation at alpha = 30 degrees, changing the concentrator position at alpha = 75 degrees has a more obvious effect on the thermal and structural characteristics of PV panel. When the concentrator moves from the designed position (e = 0 mm) to the deviated position (e =-45mm) at alpha = 75 degrees, the maximum thermal stress and maximum deflection of cells are dropped by 30.12% and 13.72%, respectively. Even if the concentrator moves the same distance, different directions (upward and downward) of movement can lead to differences in the thermal and structural characteristics. The change trend and magnitude of average electrical efficiency with the position of concentrator when alpha = 30 degrees are both opposite to those when alpha = 75 degrees. The average electrical efficiency at alpha = 30 degrees decreases from 7.76% at the designed position (e = 0 mm) to 7.62% at the deviated position (e = - 45mm), while the average electrical efficiency at alpha = 75 degrees increases from 9.26% to 10.54%.