Impact of structured glass on light transmission, temperature and power of PV modules

PV modules were fabricated using structured glass and investigated for the effect on light transmission and module temperature. Four different types of commercially available structured glass were investigated: grooves, pyramids, inverted pyramids and a very light structured type with only 5% increased surface area, along with flat glass modules for experimental control purposes. Measurements of light transmission were collected as a function of angle of incidence using an AM 1.5 G pulsed solar simulator. Results show an increase in Isc of up to 3.2% for pyramid structures with normally incident light, and the gain increases at higher angles of incidence. Wind tunnel testing was used to evaluate the effect of structured glass on module temperature. It was found that the surface structure has a significant cooling effect, increasingly pronounced at higher wind speed. In an outdoor environment, there were observed to be competing influences on module temperature: at low wind speed and high irradiance the increased light transmission associated with structured glass serves to increase module temperature, whereas at higher wind speeds, the increased convective module cooling serves to decrease the module temperature. Both the decreased temperature and increased light transmission will serve to increase the power output of the textured glass modules.