Created by M.H., BFH, on 16.02.2024
General
PV systems on house roofs usually have a module inclination that optimises the energy yield in summer or all year round. This means that the systems produce little energy in winter, even though a lot of energy is needed for heating, among other things, especially at this time of year. Vertically installed systems provide a remedy. These systems can be installed in open spaces or on flat roofs. In alpine areas, such systems can provide a significant increase in energy production due to the snow and high albedo values, as well as the almost non-existent fog. The handbook presents dimensioning diagrams for bifacial, vertical PV systems on the Central Plateau and in the Alps. On the one hand, the effect of the row spacing on the area yield and the specific yield is analysed. On the other hand, the curtailment losses are shown as a function of the nominal power ratio.
Procedure
Two locations are selected for the creation of the dimensioning graphics. One is Burgdorf as a typical location on the Central Plateau and the other is Gütsch as a representative of an Alpine location. At both locations, energy yields for different design cases are determined with the help of a predefined example system and a simulation tool. The orientation of the system and the row spacing are varied. The energy yield, the area yield and the specific yield for different seasons are determined. Values are determined for the whole year, the summer half-year, the winter half-year and the winter months. When calculating the curtailment losses, it was analysed how high the energy loss is at different nominal power ratios. The nominal power ratio describes the ratio of the power of the inverter (AC power) and the standardised module power under STC (DC power).
Results
As a result, various dimensioning graphs for the two locations are presented in the manual. The yield graphs show the course of the energy yield over the year with different row spacings. The graphs on the specific yield show the energy yield standardised with the existing system output. The graphs with the area yield reflect the possible energy yield that can be achieved with the simulated system per area. The specific yield and the area yield are compared at a high resolution with regard to the row spacing. The graphs on the curtailment losses show the losses that occur with different ratios of inverter output and module output.
