Energy efficiency and optimised wallwashing: relighting the Vorarlberg State Library, Bregenz

With a major refurbishment of the lighting system at the Vorarlberg State Library, ERCO LED lighting tools convinced thanks to good glare control of the luminaires, highly precise light distribution and low energy consumption. The project benefited from the architectural luminaire producer's many years of experience in the form of professional wallwashing with maximum levels of uniformity.

The Vorarlberg State Library located in the town of Bregenz on Lake Constance is housed in a highly unusual building – a former monastery accommodates the central book collection of the most westerly Austrian federal state. Constructed at the beginning of the 20th century by a Swiss Benedictine convent as a refuge, after the order was forced to leave Switzerland due to internal political reasons at the end of the 19th century, the monastery only served its original purpose for a few decades. After being used temporarily as a school, the state library took up residence at the site from 1986, and corresponding reconstruction of the former monastery was completed in 1993.

A highly unusual spatial construction
The splendour and centrepiece of the building has always been the large reading hall accommodated in the former abbey church, a domed central room of expansive dimensions. A peripheral gallery accessible by steps was integrated to make better use of the hall, and in particular to exploit its significant height. Part of the gallery forms an intermediate ceiling with reading places with the bookshelves towering high above the gallery in two parts of the space, extending to a height of four storeys, and spiral staircases and narrow balconies surrounding the literary treasures. The area below the dome was kept free of installations to avoid disrupting the spatial impression, and this part of the hall is often used for events.

Ambitious targets: energy independence in Vorarlberg
During reconstruction of the domed hall in 1993, ERCO supplied a low voltage based lighting system that delivered highly reliable operation over many years. More than two decades later, this system had outlived its usefulness and required upgrading to meet current requirements. The primary concern was energy consumption – a topic that Vorarlberg has attached particular importance to for several years. As a consequence, in 2009 the Vorarlberg state parliament declared its target of achieving energy self-sufficiency in the region to 2050. The aim is to meet regional energy needs by this date entirely from its own, renewable energy sources. An essential lever for implementing this ambitious plan is the significant improvement of energy efficiency across all consumption levels. Based on this, those responsible in Bregenz took the decision in 2014 to refurbish the ageing lighting system of the library in its entirety. There were also other good reasons for upgrading the low voltage system to state-of-the-art LED technology: LED luminaires enable the thermal load on books to be reduced significantly, and the wish to control light according to needs also becomes possible.

LED relighting: focus on vertical illuminance
As they were in 1993, ERCO products were used once again for upgrading the state library to LED technology. The order was not a matter of course for ERCO – a sampling process took place before commissioning, during which ERCO luminaires had to prove their worth against several competitors, including a provider based in the region. This was a success thanks to the superb energy efficiency of ERCO lighting tools and also because of their outstanding photometric qualities. The lighting design of the library that remained largely unchanged during the relighting project is based extensively on vertical illuminance: light is primarily guided onto the book shelves, helping to find sought-for titles and attracting attention to what really makes a library – its stored knowledge. Wallwashers with outstanding glare control and highly homogeneous light distribution are decisive for implementing this concept, enabling perfect illumination of the books in all shelving sections. "Only ERCO was capable of providing wallwashers that really earn this description because they bring the light uniformly right up to the edge of the wall surface," summarised Manfred Remm, lighting designer in Dornbirn responsible for the project, commenting on the sampling process.

Extreme energy efficiency and outstanding light quality
Upgrading the lighting technology achieved a 73% reduction of energy needs for lighting in Bregenz – without any modifications to the lighting design. Even when one considers that a small proportion of these savings is diminished by a slightly increased need for heating energy, heat dissipation from the LED luminaires is negligible – making an appreciable difference in total. This once again demonstrates the economic and ecological potential provided by state-of-the-art ERCO LED lighting technology.
For Manfred Remm, entrusted with lighting the library in 1993, the relighting project not only provides a positive energetic effect. He also sees his original lighting design reinforced with the new lighting technology. Remm commends the precision of ERCO luminaires that emit light onto the targeted surface without spill light, their true-to-nature colour rendering, their consistent light colour across product ranges and the outstanding uniformity of light distribution. This all contributes to a harmonious spatial appearance and aids orientation.