University of Natural Resources and Life Sciences, Vienna (BOKU) - Research portal
Gewählte Doctoral Thesis:
Michael Revesz
(2020):
The reflected irradiance inside an urban environment – Its role and improved modelling for building integrated photovoltaics.
Doctoral Thesis - Institut für Meteorologie und Klimatologie,
BOKU-Universität für Bodenkultur,
pp 106.
UB BOKU
obvsg
FullText
- Abstract:
- With the goal of satisfying our energy demand with renewable sources, there is an increasing need to model the solar potential on facades in the urban environment. However, in estimations specifically for the urban solar potential the portion of solar radiation that is reflected from the ground onto the buildings is not considered satisfactory. Knowing the solar radiation inside an urban canyon not only concerns photovoltaic systems for electricity production, but also topics such as the urban heat island effect, climate change or the thermal comfort of the pedestrians. The aim of this work was first, to identify shortcomings of solar resource models with regard to the reflected radiation. Then the portion of radiation reflected inside a street canyon compared to the total radiation was determined to assess relevance of the topic and further needs. Finally, the existing tool SEBE (Solar Energy on Building Envelope) was improved regarding the reflected radiation component and published as SEBEpv. This tool can be used to estimate the solar potential of facades in the urban environment. The improved tool SEBEpv was validated using more than two years of measurement data. However, multiple reflections were not considered in the current state, resulting in an estimated bias of a few percent. Using the example of a street canyon oriented east-west at the University of Natural Resources and Life Sciences, Vienna, Austria, the irradiation at a south-facing facade was measured and modelled. The measurements showed that the reflected component is significant. Based on view factors the expected photovoltaic yield was estimated 12 m above ground. Increasing the ground-albedo from 0.13 to 0.5 for the whole street, corresponding to highly reflective concrete, yields were expected to increase by 7.3 %. SEBEpv was used for a case study assessing photovoltaic yields in dependence of the ground's albedo, facade orientation and photovoltaic technology.
- Betreuer: Weihs Philipp
- 1. Berater: Mursch-Radlgruber Erich