Triple-junction array generates kilowatt power
Engineers have deployed and tested what is believed to be the first ever terrestrial triple-junction solar array rated at over 1 kW.
Developed by a team comprising the NASA Glenn Research Center, Boeing and Texas-based Entech, the concentrator array provides over 200 W per square meter power output at 600 V operation.
The achievement promises to improve solar power generation in space using high-voltage arrays. It also demonstrates that future terrestrial concentrator arrays based on triple-junction (GaInP/GaAs/Ge) cells could achieve unprecedented performance at an affordable price.
Looking longer-term, the successful deployment could represent one of the first steps on the way to developing a space-based energy source capable of beaming power down to Earth via a laser beam.
The solar concentrator array, which was deployed near to the summit of Mount Haleakala, on the island of Maui in Hawaii, used 240 Spectrolab GaAs P/N solar cells to convert sunlight into energy. Two concentrator modules formed the array.
According to the team, the peak power output of one of the concentrator modules reached 670 W, almost twice that of a standard module based on silicon solar cells.
The typical energy output of the array is quoted as 16 kW hours per day.
If the module was to be deployed in space, the 200 W per square meter conversion figure should increase by over 50%. Improvements in array design that have already been identified, such as the use of wider cells and improved optics, ought to improve power output by 20%.
"Further refinements will make the concepts developed in this experiment usable for space applications, allowing for large weight reductions for ion thrust systems and power beaming," concluded the team.
Details of the deployment will be discussed in a presentation at the "Solar Power from Space" conference being held in Granada, Spain, at the end of this month.
