High concentration tests of a dense PV array using GaInP/GaAs/Ge triple-junction cells in the high flux solar furnace

This paper describes the high concentration tests that were done at the NREL High Flux Solar Furnace (HFSF) with Spectrolab's assembled dense PV arrays using multi-junction (MJ) cells. The HFSF offers an excellent means of testing MJ cells under concentration because the concentration level can be maintained constant during the test, and the flux incident on the array is fairly uniform. Further, active cooling of the array by a water chiller enables obtaining data at different temperatures. High concentration tests have demonstrated the viability of the MJ cells to perform under high concentration. The tests underscored the impact of the package design and the assembly processes on the robustness of the MJ cells under concentration.