Photovoltaic modules generate heat while generating electricity. If the BIPV modules are integrated into the building envelope, this may not only reduce the efficiency of electricity generation, but also affect indoor comfort. Should additional cooling be required as a result, this will increase energy consumption.
Three photovoltaic modules with different glass backsheets are installed at the LandGlass Technology stand at glass technology live. The compared modules are equipped with 3.2-mm cadmium telluride photovoltaic cells and 1.14-mm PVB. The first photovoltaic module (#1) is on 4-mm tempered glass, the second (#2) on 8.3-mm vacuum-insulated glass and the third (#3) 20-mm insulated glass. Above the stand is a light source consisting of nine sets of iodine-tungsten lamps, each with a power of 1000 W. The temperature of the upper and lower surfaces of the PV modules is measured in comparison, while simultaneously monitoring the power generation. This makes it possible to determine how the PV modules for building integration should be configured in order to achieve an optimal result.
Based on the values of the lower surface temperature, the following temperature ranking of the three modules results: 2#<#3<#1. The lower surface temperature is positively correlated with the U-value of the PV modules. The photovoltaic vacuum-insulating glass module (#2) has the lowest U-value, which results in the lowest temperature on the lower surface. When using this module, the amount of heat transferred to the room in relation to the electricity generated is therefore the lowest, making this configuration the recommendation for building-integrated photovoltaic systems.
