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Glare from photovoltaic systems

Hjorth, Erik LU and Wochele, Florian LU (2017) AEBM01 20171
Energy and Building Design
Abstract
With an increasing usage of photovoltaic panels also in urban context the cases of glare caused by photovoltaic systems are raising. Many countries have low or no regulations regarding outdoor glare caused by daylight, therefore legal cases can be complicated.
Even though there are thresholds agreed upon for glare indoors there are no thresholds determined for outdoor daylight glare situations, therefore the thresholds suggested so far are compared. Due to the lack of an approved assessment method the aim of this study is to create a method which can be used to assess glare from photovoltaic panels. A comparison study based on the method of the Daylight Glare Potential and a study to determine thresholds for the sun disk luminance were... (More)
With an increasing usage of photovoltaic panels also in urban context the cases of glare caused by photovoltaic systems are raising. Many countries have low or no regulations regarding outdoor glare caused by daylight, therefore legal cases can be complicated.
Even though there are thresholds agreed upon for glare indoors there are no thresholds determined for outdoor daylight glare situations, therefore the thresholds suggested so far are compared. Due to the lack of an approved assessment method the aim of this study is to create a method which can be used to assess glare from photovoltaic panels. A comparison study based on the method of the Daylight Glare Potential and a study to determine thresholds for the sun disk luminance were performed to evaluate the functionality of the suggested method. It can be concluded that with additional verifying studies the method can be a way to decrease the cases of glare caused by photovoltaic systems and raise the awareness of this problem already during the planning phase. (Less)
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Developing an assessment method in order to determine glare caused by reflections of solar panels

The increased usage of solar energy does not only have positive effects. Unfortunately, the amount of glare caused by reflections occurs with increased frequency. The awareness that measures must be taken against the human-caused climate change is increasing and results in an increase in the installation of renewable energy sources. One of the renewable energy sources is the usage of photovoltaic panels, which transfer the energy of the sun into electrical energy. Consequently, problems caused by reflections of photovoltaic panels onto neighbouring buildings are rising. In order to determine the time, place and strength of these undesired reflections, the assessment method described in this thesis was developed.
Even though glare is not a new phenomenon it is mostly considered within indoor situations like offices with artificial lighting. Glare caused by the reflection of a photovoltaic panel is however caused by the sun itself and since existing methods are usually focused on indoor situations they could not be applied here. With the developed assessment method, it is possible to determine glare without a particular indoor situation. Therefore, it can already be used in an early planning process or when there is a legal case between neighbours. Even though it is proposed for photovoltaic panels the assessment method can be used for all kind of surfaces, for example windows or metal facades.
Currently, photovoltaic systems are planned according to the need of the owner without regards to the impact on third parties. The reason for this is that there are no regulations stating that studies about the impact on third parties must be done. Only few countries have regulations considering the reflections of photovoltaic panels, however, these regulations are lacking a legally binding status. A study on legal cases showed that in some of the cases the guidelines were mentioned. However, due to the lack of a binding regulation it was not considered during the decision making.
The developed method can be used with a three-dimensional model of the surrounding area and the panel geometry. In an initial step only the needed geometry is selected. Based on that selected geometry there are geometrical calculations carried out in order to determine the times and places in which reflections occur. Based on these results simulations regarding the luminance of these reflections can be conducted. With a combination of the results of the geometrical calculation as well as the simulation the times and areas with glare can be shown both in the model itself and in diagrams.
These diagrams and visualisations in the model then help to determine if there is a need of alteration of the proposed system or if the system can be installed in that specific way.
The results can be either shown in the three-dimensional model for individual times or all the results can be shown at the same time giving a general idea of the location of affected areas. With the presentation in diagrams it is possible to show how often and at which times glare occurs. Processing the results even further makes it possible to show only glare periods with a substantial duration. This can be helpful in the combination with the guideline mentioned above. (Less)
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author
Hjorth, Erik LU and Wochele, Florian LU
supervisor
organization
course
AEBM01 20171
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
8916532
date added to LUP
2017-06-22 12:59:42
date last changed
2017-07-05 09:32:12
@misc{8916532,
  abstract     = {With an increasing usage of photovoltaic panels also in urban context the cases of glare caused by photovoltaic systems are raising. Many countries have low or no regulations regarding outdoor glare caused by daylight, therefore legal cases can be complicated.
Even though there are thresholds agreed upon for glare indoors there are no thresholds determined for outdoor daylight glare situations, therefore the thresholds suggested so far are compared. Due to the lack of an approved assessment method the aim of this study is to create a method which can be used to assess glare from photovoltaic panels. A comparison study based on the method of the Daylight Glare Potential and a study to determine thresholds for the sun disk luminance were performed to evaluate the functionality of the suggested method. It can be concluded that with additional verifying studies the method can be a way to decrease the cases of glare caused by photovoltaic systems and raise the awareness of this problem already during the planning phase.},
  author       = {Hjorth, Erik and Wochele, Florian},
  language     = {eng},
  note         = {Student Paper},
  title        = {Glare from photovoltaic systems},
  year         = {2017},
}