Environmental and energy analysis for photovoltaic-thermoelectric solar unit in existence of nanofluid cooling reporting CO2 emission reduction

Abstract

BackgroundIt is crucial to introduce new strategies to intensify the efficiency of photovoltaic thermal (PVT) unit. The incorporation of a thermoelectric generator (TEG) within a solar unit can notably improve its electrical performance. Additionally, modifying the properties of the cooling fluid by incorporating nano-powders proves to be an effective approach in optimizing PVT systems. MethodsThis study delves into an inventive design for a PVT unit, exploring novel techniques to boost its performance. To enhance the cooling of the PV component, two strategies were employed: 1) the implementation of a new-style turbulator, and 2) the integration of confined jets. Thus, three cases were simulated: case 1 (without any enhancement), case 2 (with the turbulator), and case 3 (employing both techniques). Additionally, the TEG layer was incorporated with the PV layers to augment overall efficiency. The testing fluid, water, was infused with SiO2 nanoparticles, and their properties were determined using a homogeneous mixture formulation. For simulating the current 3D model, the Finite Volume Method was chosen, accounting for laminar flow in fluid zones and applying the pure conduction equation for solid zones. The impacts of altering geometry, heat flux (G), inlet velocity within the tube (Vi), and jet (Vj) on performance metrics (including PV electrical (ηPV), thermoelectric (ηTE), thermal (ηth), overall electrical (ηEl), total (ηTot)) have been detailed in the results section. Significant findingsBy implementing two cooling techniques, the uniformity of panel temperature experiences a notable enhancement of about 79.96 %. With an increase in the velocity of the nanofluid within the tube, there is an approximately 1.99 % improvement in the value of ηTot. Furthermore, when Vi=0.08 m/s, the values of ηEl, and ηTot see an increase of about 3.09 % and 12.59 %, respectively, upon the installation of the jet and turbulator. An augmentation in G leads to a rise in ηTot by approximately 5.32 % and 7.32 % for cases 1 and 3, respectively. When G = 810 W/m2, incorporating a jet and turbulator in the PVT system results in improvements of about 2.64 % in ηEl, and 10.45 % in ηTot. The increment of ηTot with switching from case 1 to case 3 enhances about 24.62 % with the rise of G. Moreover, as the inlet velocity of the jet increases, the values of ηTE, ηth, and ηTot enhance by about 3.43 %, 1.87 %, and 1.06 %, respectively.