Computational Analysis of Nanofluid Cooling of High Concentration Photovoltaic Cells

Abstract

High concentration photovoltaic devices require effective heat rejection to keep the solar cells within a suitable temperature range and to achieve acceptable system efficiencies. Various techniques have been developed to achieve these goals. For example, nanofluids as coolants have remarkable heat transfer characteristics with broad applications; but, little is known of its performance for concentration photovoltaic cooling. Generally, a cooling system should be designed to keep the system within a tolerable temperature range, to minimize energy waste, and to maximize system efficiency. In this paper, the thermal performance of an Al2O3-water cooling system for densely packed photovoltaic cells under high concentration has been computationally investigated. The model features a representative 2D cooling channel with photovoltaic cells, subject to heat conduction and turbulent nanofluid convection. Considering a semi-empirical nanofluid model for the thermal conductivity, the influence of different system design and operational parameters, including required pumping power, on cooling performance and improved system efficiency has been evaluated. Specifically, the varied system parameters include the nanoparticle volume fraction, the inlet Reynolds number, the inlet nanofluid temperature, and different channel heights. Optimal parameter values were found based on minimizing the system's entropy generation. Considering a typical 200-sun concentration, the best performance can be achieved with a channel of 10 mm height and an inlet Reynolds number of around 30,000, yielding a modest system efficiency of 20%. However, higher nanoparticle volume fractions and lower nanofluid inlet temperatures further improve the cell efficiency. For a more complete solar energy use, a combined concentration photovoltaic and thermal heating system are suggested.

Experimental and numerical investigation of heat dissipation from an electronic component in a closed enclosure

“…Properties of air and water (de-ionized) possess similar trends but among them water has high heat transfer coefficient. Z. Xu [13] validates that to get maximum efficiency, the CPVs should be under a suitable temperature. The rate of increase of efficiency as Re increases is higher at low range of Re values and then get reduced.…”

Performance analysis of a copper sheet laminated photovoltaic thermal collector using copper oxide – water nanofluid

“…A 3.6% and 7.9% improvement on using 1% and 3% weight fractions respectively were observed for silica/water nanofluid (Sardarabadi et al, 2014). The computational analysis of a concentrated PV cell was investigated using Al 2 O 3 /water nanofluid (Xu and Kleinstreuer, 2014). The performance of the solar PV panel cooled on the top surface using nanofluids was studied for different mass fractions, fluid thicknesses (Cui, 2012), and their light transmittance and thermal conductivity using Silica/water nanofluid were tested using 2D CFD model for different nanoparticle sizes, light concentrations and velocities (Jing et al, 2015).…”

Mathematical Modeling and Computer Simulations of Nanofluid Flow with Applications to Cooling and Lubrication

“…For example, Kleinstreuer and Feng [96] proposed a model based on Brownian motion-induced micro-convection. Xu and Kleinstreuer [15] enhanced the F-K model to include the local clustering effect as well as the interfacial thermal resistance effect. The model divides the thermal conductivity k n f of the nanofluid into a static part and a micro-mixing part, i.e., k n f " k static`kmm .…”

“…Over the last several decades, there has been an ever-increasing interest in nanofluids, i.e., liquids with all sorts of solid nanoparticles (NPs) well dispersed at low concentrations. Application areas for nanofluids range from engineering to medicine, taking advantage of their unique properties in heat transfer [1][2][3], drug delivery [4][5][6][7], mass transport [8,9], boiling phenomena [10,11], absorption and radiation [12][13][14][15], optics [16,17], reacting surfaces and catalysts [18], spray-coating [19,20], and lubrication [21][22][23][24]. Though initially investigated in the heat transfer community (see [25]), the concept of "nanofluids" is being continuously expanded in developing more and more useful applications.…”