The importance of sensors in the determination of BIPV parameters and installation energy yield

Sensor reliability is important in building integrated photovoltaic installations to convey confidence in the correct operation of the installation and to quantify the yield of the PV system. This paper relates the experience gained from a PV facade installed at Southampton University, which was found to have irradiance sensors (reference cells), producing conflicting data. Specifically, when comparing the output of the various irradiance sensors it is apparent that performance ratio analysis of the PV system produces widely differing results. This paper discusses the critical impact of sensor accuracy on array power output and performance ratios. It serves to highlight that even small errors in irradiance measurement can determine whether or not a PV system is perceived as being 'good' based on its performance ratio.