Natural convection in inclined channel for air cooling of photovoltaic panels

Abstract

Reducing the operating temperature of a photovoltaic (PV) module is an effective way to improve efficiency and prevent damage from overheating. The present paper focuses on the study of the effect of inclination on air natural convection in an asymmetrically heated channel (at uniform heat flux), in laminar regime. This configureuration models the passive and natural air-cooling of PV panels by inclined chimneys. The computational procedure solves the unsteady two-dimensional Navier-Stokes and energy equations by a finite volume approach while the projection method decouples the pressure from the velocity. The heat transfer and fluid flow are analyzed for a wide range of modified Rayleigh numbers varying from 102 to 105 and for inclination angles between 15o and 90o with respect to horizontal position. The results show that the mass flow rate and the average Nusselt number increase with the angle of inclination as well as with the modified Rayleigh number. However, a significant reduction in heat transfer rate and induced flow rate is observed for the low angles of inclination. To enhance the cooling of the PV panel, extensions are added at the inlet and outlet of the channel. The simulations show that only the downstream extensions of the channel are effective in improving the induced mass flow rate and therefore the convective heat transfer.

ZnO-based sensors with controlled ethanol sensing

“…Therefore the sensing properties are easily influenced by the micro-structural features, such as the grain size, crystal structure, geometry and connectivity between particles [6].ZnO is a semiconducting metal oxide which has received a great deal of attention from researchers and industry alike [7][8][9][10]. Since the discovery in 1962 that the electrical conductivity of ZnO could be dramatically changed by the presence of reactive gases in the air, there have been tremendous reports on the applications of ZnO as gas sensors [11][12][13][14][15][16][17][18]. Extensive studies have been put on improving the sensing performances based on the ZnO gas sensors, aiming at improving the sensitivity, response/recovery, selectivity, stability and feasibility for practical use [19,20].…”

Structural and optical properties of tin sulfide nanostructures

“…Researches were conducted on laser processing of semi-conductor thin film structures and studies on photo-induced changes in the structural, morphological and optoelectronic properties of various thin film materials [9][10][11][12][13]. Continuous wave 532 nm laser irradiation resulted in modifications on the structure, morphology and optoelectronic properties of Sb 2 S 3 thin films [14] and Sb 2 S 3 :C/CdS multilayers [15].…”