Energy Efficient Two Phase Microcooler Design for a Concentrated Photovoltaic Triple Junction Cell

Abstract

The potential application of an R134acooled twophase microcooler for thermal management of a triple junction solar cell (CPV), under concentration of 2000 suns, is presented. An analytical model for the triplejunction solar cell temperature based on prediction of twophase flow boiling in microchannel coolers is developed and exercised with empirical correlations from the open literature for the heat transfer coefficient, pressure drop, and critical heat flux. The thermofluid analysis is augmented by detailed energy modeling relating the solar energy harvest to the “parasiticâ€‌ work expended to provide the requisite cooling, including pumping power and the energy consumed in the formation and fabrication of the microcooler itself. Three fin thicknesses, between 100 خ¼m and 500 خ¼m, a variable number of fins, between 0 and 9, and 5 channel heights between 0.25 mm and 3 mm, are examined for a R134a flow rate of 0.85 g/s to determine the energy efficient microcooler design for a 10 mm أ— 10 mm triple junction CPV cell.