Performance Analysis of Vertically Mounted Bifacial PV Modules on Green Roof System

Autor: Baumann, Thomas, Carigiet, Fabian, Knecht, Raphael, Klenk, Markus, Dreisiebner, Andreas, Nussbaumer, Hartmut, Baumgartner, Franz
Jazyk: angličtina
Rok vydání: 2018
Předmět:
DOI: 10.4229/35theupvsec20182018-6ao.9.4
Popis: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1504-1509
A combination of PV and green roof is an ideal fusion in terms of ecology. The green roof improves the water retention in the city, whereas the PV system produces electric power at the place where it is consumed. Flat tilted modules in south or east west direction on green roofs generally require intensive maintenance to prevent them from being shaded by plants and often cover the roof area to a large extent. Because of the space requirement conflict between PV on the roof and green roofs, it is essential to combine these two systems in a smart way. Vertically mounted bifacial modules can be an option to combine PV and green roof and to also allow a cost-effective maintenance. In this paper we report about the layout and the performance of a corresponding system, subdivided into two groups with differing albedo. Custom made bifacial modules with 20 cells were produced to reduce the wind load and to improve the general appearance. This 9.09 kWp bifacial plant achieved a specific yield of 942 kWh/kWp in one year (11.08.2017 to 10.08.2018). High quality DC power measurement systems are installed to monitor two modules in each bifacial test field and a reference south-facing module. This allows an energy yield comparison between the vertical bifacial test system with east-west orientation and the monofacial south-facing reference over four months of outdoor measurements. The use of plants with good reflective properties, which are also well suited two the ambient conditions on flat roofs, resulted in a yield increase of 17 % compared to a standard green roof planting. The vertically installed bifacial modules obtained an almost identical specific yield (-1.4 %) compared to a stand-alone monofacial southfacing reference module. Due to the increased yield in the mornings and afternoons, the vertical bifacial modules can achieve higher self-consumption depending on the load profile.
Databáze: OpenAIRE