The background
In buildings like the Würth Elektronik eiSos Head Office, which face south with large areas of windows, cooling in summer plays an enormous role in terms of energy consumption – in many cases it is even more important than energy input in winter.
Generally, direct sunlight is prevented by the use of shading elements.
But an interesting effect has been observed:
the optimum angle of a shading element is almost identical to the angle of a photovoltaic module installed to achieve the best possible output of solar energy. So, what could be more practical than combining the functions of shading and photovoltaic modules?
The solution
Within the scope of a coordinated air conditioning concept, in addition to an integrated system for cooling parts of the building with temperature controlled concrete ceilings, Würth Elektronik eiSos also decided to employ photovoltaic technology.
The solar modules fulfil a double function: they were installed on the glass façade in such a way that they block the heat from the summer sun and thus prevent the building from heating up. At the same time, around 50 metres of photovoltaic modules installed in two rows generate about 8,000 kWh of electricity during the approximately 1,000 hours of sun per annum.
In the planning phase it was especially emphasised that in spite of the shading elements, enough daylight had to enter the offices at all times of the year so that staff can work without the need for artificial lighting. This problem was resolved in cooperation with lighting designers.
To optimise the shading and power generation results, the system has an automatic sun tracking system with 20 linear drives that move the modules around their middle axis.
Two floors were each equipped with 40 CIS modules in a customer-specific size of 1,150 x 1,200 mm. The modules themselves are suspended between the carriers of the mounting system and were produced on the basis of the building supervisory authority specifications and an expert opinion from a static engineer. The cables were installed in the cavities of the mounting system.
The functions of the PV system are monitored easily and in a user friendly manner via a data logging system. The solar power generated at any given time and also the total amount that has been fed to the grid since the system was put into operation is continuously visualised for staff and visitors.
The combined shading and photovoltaic system is not only integrated seamlessly into the building's overall aesthetics, by feeding the solar power to the grid it produces a zero energy balance for the office building and is thus not only convincing in terms of form, but also in terms of function.
"When we began planning our new administration and sales centre in Waldenburg, one thing was especially important to us. We wanted an industrial building with warehouse and administration facilities that took new paths in terms of both architecture and technology - true to the company's motto "more than you expect".
Staff had to feel good in our new home and, at the same time, we wanted to set new benchmarks in terms of reducing operating costs.
The CIS technology from Würth Solar became an important building block in the air conditioning concept for our building. With this combination of integrated building element cooling by means of temperature controlled concrete ceilings, shading with automatic sun-tracking Würth solar modules and photovoltaic power generation, we have achieved an energy cost balance that has certainly convinced the architects, designers and us as customers.
Staff as well as visitors quickly realise the advantages of the building - uninterrupted views all day long, pleasant temperatures and good light conditions at the workplace. The response of visitors to the aesthetics of our building confirm that we made the right choice with the uniform black photovoltaic modules."
(Oliver Konz, Managing Director Würth Elektronik eiSos GmbH & Co.KG, Waldenburg, Germany)
The technology
- Number of modules: 80, 40 of them laminated safety glass and 40 as standard laminated glass
- Width (mm): 1,150
- Length (mm): 1,200
- Installed nominal output: 8 kWp
