ENERGY EXEMPLARS

A combination of efficient light sources, daylight and solar generation is the key to a radical building. Pennie Varvarides reports

SMA Solar Technology’s new training centre at Niestetal in Germany is harnessing the power of sunlight to minimise energy consumption.

The owners wanted to create a motivating atmosphere for trainees, and the lighting design by Lichtvision was designed to support this goal, maximising the use of solar power.

The emphasis on solar power is no surprise, given that SMA produces and distributes solar inverters and monitoring systems for photovoltaic (PV) applications.

Isabel Sternkopf, a senior associate at Lichtvision, says: ‘Solar inverters are technologically the most important components in any solar power system because they transform the direct current produced by solar modules into grid-compliant alternating current.

‘A convincing way to demonstrate the practicability and sustainability of solar technology is to design a public building independent of any power distribution grid, showing at the same time that a comfortable atmosphere, without giving up any conveniences, can be achieved easily.’

Power portions

There are PV modules on the roof and in the glass façade. Surplus power from the PV modules is storedin high-capacity batteries.

The building consumes 130MWh of energy a year and the input from the PV modules is 142MWh. Another 55MWh comes from a biogas-fuelled combined heat and power (CHP) plant.

Sternkopf says: ‘The battery will never be fully emptied. If the battery’s state of charge reaches a critical point, the biogas-fuelled CHP plant will start producing extra electricity.

‘As soon as surplus power from solar modules is available the batteries start recharging.’

A green LED display at the entrance shows the building’s energy consumption or the solar gain.

The status of the Solar Academy’s energy systems is also indicated by the colour of the corridor washlights, which changes with the battery’s charge – green when high and red when low.

By showing visitors how much energy is being collected and used throughout the day, the building raises visitors’ awareness of the importance of saving energy.

An LED display shows the solar gain or the building's energy consumption

Sternkopf says: ‘Theoretically, [a full battery would last] five hours under full-load operation. In practice there would never be a situation of full load, because the lighting and all other electricity-consuming devices are controlled as required depending on thetime of day.

‘There has been a focus on energy saving with the help of intelligent control systems.’

The CHP plant produces heat and supplementary electricity when the PV modules do not supply enough power. During the winter months, when sunlight is limited, the building operates as normal.

Sternkopf says: ‘The CHP plant is only used when solar gain is not suf cient and the battery’s charge is too low.’

On the demand side, dimmable T5 fluorescents and extensive use of daylight cut energy consumption and heat generation.

A  first floor lounge is illuminated by recessed downlights. In nearby corridors, lighting is built into the architecture, so the ceiling is clear of lighting equipment clutter. Light from LED sources is controlled by lenses.

Dimmable ceiling-recessed linear fluorescent profiles echo the rhythmic pattern in the entrance zone


Guided by the light

On entering the building, visitors are guided to the staircase by a rhythmic pattern of luminaires and increased illumination on the  oor. The reception area is lit by dimmable ceiling-recessed linear fluorescent pro les in the same pattern as in the entrance zone.

The canopied space is lit by LED spots built into the ceiling. It can be used as a temporary event area.

Lichtvision avoided the use of uplights and indirect lighting to reduce wasted energy and light pollution in the surrounding areas.

Construction work started on the project in May 2009 and it was completed in August 2010. Of the £6million budget, £104,000 was spent on developing the lighting – less than 2 per cent of the total.

Sternkopf says: ‘To be honest, at the beginning I was sceptical about whether it would be possible to design a public building without access to any power distribution grid. The client was very open minded and allowed us to implement unusual solutions. The building works very well and the client is satisfied.’

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