Post installation optimisation of a building integrated PV system at Southampton University

The deployment of building integrated photovoltaics in the urban environment represents an opportunity for energy production and use at source. It also has a positive impact on expanding the market for photovoltaics resulting in reduction in cell and systems costs. An example of such a system is the subject of this paper. The operation of the photovoltaic facade installed at Southampton University is constantly monitored. In addition to system energy yields, the mismatch losses, notably at low irradiance levels and during periods of shading, were measured and evaluated. The determination of the operational characteristic of each string in the array is critical in identifying the interactions that may occur between strings, and the resultant degrading effect on system performance. The results indicate that the original design configuration of the strings of the array, determined as the optimal from theoretical and conventional principles, is not the most efficient. After optimisation of the connection characteristics of the 24 strings in the array, an increase of 8% in system efficiency was achieved.