Fig. 4: Outdoor power-generation performance at representative times (prototype modules atop the hemispherical domes were installed on a horizontal surface).
a Magnifications of the prototype modules in the experimental setup. b, c Measured Pmax and irradiances (direct horizontal irradiance (DHI), diffuse irradiance) as a function of the sun’s position on May 17, 2019 (Nagaoka city, Japan). String directions were (b) east–west in AM and (c) north–south in PM. String 1 lay on the northern side in AM (black bar referred to as “N”) and on the western side in PM (black bar referred to as “W”); string 2 lay on the center line of the hemispherical dome (blue bar referred to as “C”); and string 3 lay on the southern side in AM (yellow bar referred to as “S”) and on the eastern side in PM (yellow bar referred to as “E”). For the solar altitude, 90° corresponded to the zenith, and for the solar azimuth, −90°, 0°, and 90° corresponded to the east, south, and west, respectively. (w/ lens, with lens; w/o lens, without lens).
