Indoor measurement of GTE-matrix for energy rating

Energy rating input data acquired indoors is currently based on IV curves measured in a matrix of irradiances (G) and temperatures (T). This can lead to uncertainties in the energy prediction as one needs to make additional corrections for the effects of spectrum (E) and angle of incidence. Energy rating measurements derived outdoors inherently take those variations into account and are more accurate for that reason, but take a long time to acquire and site to site differences might show up more strongly. This paper demonstrates the first indoor GTE matrix measurements made with an LEDbased solar simulator prototype, opening the possibilities of much faster and more accurate energy rating of PV devices. The experimental set-up and measurement method used is explained in detail. Analysis shows a respectable uncertainty of 3.2% (k=2) in maximum power measurements with scope for further improvement.