Electrical Engineering - Photovoltaics

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Photometry - Solar Glare Assessments

Solar Glare Assessments are often required as expert input in building permitting submissions of solar power plants or glass facades, especially when glint and glare in the direction of the neighbourhood or road traffic cannot be ruled out. Guidelines in different countries allow the assessment of solar reflections. On one hand, they review the duration of the glare (during a day and during a full year) as criterion of assessment. On the other hand, the strength of the reflection can play an important role in the perception of the glare.

The impression of brightness in the human eye is determined by the Luminance, measured in cd/m² (Candela per square-meter). The brightness of a surface is defined by the value of the Illumination, measured in lx (Lux).

Solar Glare Assessment for Dubai Airport

PV-Roof-Top with Megawatt-Size

Dubai Airport Terminal 2, which has been around since 1998, at this moment is undergoing renovation and expansion, having its capacity doubled. The flat roof of the Terminal with its size of 63,000m² is an ideal site for a PV-plant. On one hand, the un-shaded area offers a lot of space for a PV-park under Dubai's sun. On the other hand, the generated electricity will be consumed in the terminal building directly under it, which will result in first-class efficiency with its short connection cables. While other utility-size power plants need expensive transformers and long transmission cables to feed-in electricity, this particular PV-plant can be connected directly to the main distribution board of the building.

Glint and Glare

Due to heavy traffic at the airport, pilots and air traffic controllers must not make any mistake. Reflections of glass surfaces could blind airport personnel at the tower. Since they have to be able to view the runways, rollways and approach sectors any time and without obstruction, reflections from PV-panels could pose a glaring hazard. In the case an air traffic controller has no visual contact to the airplanes, he has to rely completely on radar-based instruments and therefore needs to increase airplane distances of starting and landing airplanes, to provide additional safety. This increase in airplane distances costs the airport valuable time - the capacity of its runways is reduced.

Solar Glare Assessment of The Shard

London, UK - Zehndorfer Engineering has finished a Glint and Glare Study of the glass facades of The Shard. The purpose of the study was the investigation of the sun reflections on the many glass facades of the high-rise building, which has reportedly caused dazzling among train drivers on the south-eastern train tracks leading to the London Bridge Terminal. Not far from the place of investigation, in 20 Fenchurch street, another building had been destroying a car when its facade reflected sun rays. While the effect of the reflections in this case are not that harmful, they still can be a nuisance for traffic and neighbours. In order to develop a full understanding of the buildings glare impact a glare simulation was done for several points of interest such as the train tracks, neighbouring roads and an adjacent building.

Safety of Photovoltaic Installations in case of Fire

On the occasion of a major fire in a maritime yard in Carinthia, Austria Mr. Jakob Zehndorfer, Expert Witness for Photovoltaics was interviewed by Austrian TV-Channel ORF, regarding the safety of Photovoltaic Installations in case of Fire. The roof of the building had been equipped with a commercial photovoltaic plant, which in case of fire can be uneasy for firemen. However, with the right approach, firefighting with a photovoltaic installation is no more dangerous that without.

Glint and Glare Assessment at the airports of Munich and Paderborn

The Airport Munich "Franz Josef Straus" (MUC) is the largest airport of Bavarian capital Munich. With its 44.6 million passengers, it ranks among the largest airports of Europe. The approximately 100 carriers, flying into Munich, connect it with almost 300 destinations in the whole world. More than 500 airplanes take off from one of its two parallel 4,000 m runways. On the roof of the central building of Terminal 2 there is already a photovoltaic installation with an approximate size of 400 kWp, which helps to reduce the CO2 emissions of the commercial buildings. However, the installation, which has been in smooth operation since 2013, has not been part of this glint and glare assessment.

PV-park in the approach sector

The planned Photovoltaic ground mount installation is situated exactly in line with the runway, approximately 5 km west of the touch-down zone. Even though the PV-park with its 10 MWp is relatively big, it can merely be seen as a thin line on the horizon due to its large distance from the tower. However, the direction of the Solar-park is the same as the runway, which means that it is an important view for air traffic controllers. Therefore, potential glint and glare of sunlight, reflected from the surface of the PV panels had to be calculated and investigated, Due to the situation and the direction of the PV panels, reflections towards the air traffic control tower were found to be principally impossible.

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