A numerical modeling of thermal management of high CPV arrays using spray cooling

Abstract

Liquid cooling is an efficient way of thermal management for high CPV cells, increasing the system performance by reducing cell's temperature. Thermal management complexity rises upon using an array of cells while the system becomes sizeable. The present numerical simulations follow a single cell study to investigate spray cooling for high CPV arrays with minimum number of injecting nozzles. The idea is to cool the cells by the liquid film formed on the thermal paste surface. Cooling the whole surface by the help of the liquid film decreases the number of nozzles to less than the number of cells. Both mass flow rate and pumping power are reduced, improving the system efficiency and lowering the liquid demands. To find cooling patterns, one-dimensional arrays with two and three cells and two-dimensional square arrays of order two and three are investigated at three solar concentrations; 500, 750, and 1000 Suns. The non-spraying cells' performance is assessed by consideration of two criteria; the damaging temperature and the increment rate of the difference between the cell power operating with and without injection. It is indicated that the patterns from smaller arrays can be applied to design the injection arrangement for the larger ones. Results from the cooling injection on a square array of order three demonstrate that decreasing the number of nozzles can reduce the mass flow rate by 55–89 % and increase the net power by 0.5–2.2 %, depending on the concentration ratio.