“Energy saving was already a high priority on the agenda before construction began in 2001 and was included in the overall plant concept from the very beginning,” explains Martin Stange, plant manager at the Regensburg facility, to visitors. At the moment he is showing a group of environmental protection officers from other OSRAM production operations around the plant, a brand new 56,000 square meter factory for semiconductor chips. He stops in front of a large green machine and explains: “That’s our absorption refrigerating machine. It converts hot 120-degree exhaust gases into cold air for air-conditioning.”

The Regensburg factory manufactures optical semiconductor chips, the core elements of LEDs. These tiny lights are one of the up-and-coming products of the future. They are small, rugged and light-intensive, and come in all colors. They are being increasingly used in the automotive industry, such as for dashboard lighting and for headlights, as well as in architectural lighting, street lights, cellphone illumination and wall displays. Since they convert electric power into light more efficiently than, say, conventional incandescent lamps, they play an important role in saving energy and reducing CO₂ emissions. LEDs are manufactured from semiconductor materials in a highly complex process. The Regensburg cleanroom production site uses state-of-the-art chip and optical semiconductor production technologies, and the plant itself is a model operation when it comes to utilization of resources, transparency, operating reliability and minimizing environmentally relevant risks.

As Stange explains, the energy saving stipulated in the planning was systematically implemented. “Our approach was to group together different energy systems in the overall supply and disposal process at the location. For instance, we use waste heat from various manufacturing processes as well as the ambient cold air naturally present in the winter months. In the summer, excess process heat is additionally converted into cold air needed at this time of year for air conditioning,” he adds.

Since the free cooling process doesn’t provide sufficient cooling in the hot summer months, it is combined with a second process. This uses the cleaned 120-degree exhaust air. In the summer, this hot air is converted into cooling energy in an absorption refrigerating machine and is likewise used for cooling. In winter, the exhaust air is directly incorporated in the existing heating system via heat exchangers and used for preheating or postheating in the building’s air-conditioning systems.

Nevertheless, the two processes alone aren’t a comprehensive energy concept. That’s why the waste heat from nitrogen extraction is also used for the heating circuit in Regensburg. Nitrogen is needed for the production of semiconductors components, including LEDs, and was formerly delivered in liquid form by specialist companies. Now it is extracted directly from the ambient air at the production site. When operating, the extraction system compressors generate waste heat which can also be used for air conditioning. Another positive effect of producing nitrogen locally is that truck deliveries are unnecessary. For Regensburg plant, this has eliminated roughly 100,000 truck kilometers each year.

As Siegfried Schäffl, environmental officer and chief security engineer at the plant, explains, all these measures allow annual energy savings of about 13 million kilowatt hours (kWh) of gas and 4.5 million kWh of electricity. With the energy prices prevailing in mid-2009, this is equivalent to 858,000 euros, less the investment costs.