User
The owner of the building rents the areas to other subcompanies of ThyssenKrupp. At the moment, all users are of the ThyssenKrupp AG, although  other tenants would also be possible.

Utilization
The "Kreuzgebäude" is a typical office building of the 1980´s. About 90% of the rooms are used as office rooms, mostly single offices, including the computer design rooms. The standard size for a single office is approx. 20 m². Further special uses for the building are a cafeteria, small kitchen, small kiosk, server room and copy area. Altogether approx. 400 employees work in the building.

Building concept
The  building floor plan has the form of a cross, therefore the name "Kreuzgebäude" was derived. A central staircase connects 4 wings with a long corridor and office rooms on both sides of the corridor. The straight facade of the wings are partly broken by honeycomb-shaped structures. In these structures open-plan offices are situated which were converted to single rooms during a renovation that is going on since 2002. Small kitchens and WCs are placed near the staircase. The building construction has a double leaf facade with clinkers and a flat roof. Since the building´s construction in 1985, no renovation was carried out on the exterior components.

HVAC concept
The heating of the building occurs through district heating delivered by the company Steag, which runs a gas-cogeneration-unit. All rooms are provided with heating elements, which can be adjusted manually by the users. Originally the small offices were not equipped with a cooling or ventilation system. However, little by little the building owner installed multi-split devices in order to provide cool air to the rooms. At the moment about 50% of the offices are equipped with these devices. Ventilation is performed manually through the windows like before and causes no disconnection of the air conditioners. The office spaces in the honeycomb structures are supplied via a supply/exhaust air system located on the roof. These 6 ventilators are equipped with reheating registers and heat recovery. The owner will gradually shut down this system and replace it with multi-split devices as in the other rooms. Additionally, several exhaust air systems are available, e.g. for the cafeteria, WC, copying area, garbage/waste area. None of these are equipped with any heat recovery system. Hot water is supplied via a heat exchanger from the district heating system and is stored in a warm water storage. All lights are fluorescent from 1985 and have been not replaced since then.

General data