Nov 1, 2014 - Building
City Nord: Reboot on the Kapstadtring
At the end of the '60s, the “City Nord” development project in Hamburg included the German headquarters for Esso. However, the inner-city collapsed during the economic boom in West Germany, which drove the decision to relocate large corporations. The building on the Kapstadtring in Winterhude, a district in northern Hamburg, was designed by the architects at Schramm and Pempelfort, also from Hamburg. Soon, after complete internal renovations, it will reopen as a modern office and administration building. The WAGO-I/O-SYSTEM 750 is an important internal foundation that ensures the 47,000 square meters of usable space can be easily adapted to employee’s needs.
Hamburg's City Nord demonstrates that the change in work processes, due in large part to the introduction of computerized workstations, has necessitated overhauling the concept of open-plan offices. This attitude change in the '90s caused an image decline for the City Nord. The building complex, designed by renowned architects of the time, failed to keep up with the times in terms of function and technology. Over the course of the City Nord revitalization, the open-plan office gave way to individual offices that were created by renovating existing buildings, new projects and tear downs.
Adapting Better to Circumstances
The four wings of the complex on the Kapstadtring unify the perseveration of historic buildings with energy efficiency and functional flexibility. The open plan has yielded to smaller segments of space that can be flexibly configured. This grid system enables the configuration of both individual workstations and spaciously configured offices for entire teams. The concept makes it possible to quickly adjust the space to meet occupants’ needs at any given moment. If offices are needed to accommodate two or three people, or an entire project team, then the necessary space can be created in a variety of high-tech ways. Demountable partition walls on their own are insufficient for achieving this flexibility. Instead, building technology, such as the heating system, must also support the desired spatial configurations.
Heat is provided via convectors located under the windows. The level is regulated using a combination of a valve-controlled hot water supply and variable speed fans. The entire system is controlled by the WAGO-I/O-SYSTEM 750. The building automation experts from Caverion Deutschland, who were responsible for the renovations, implemented the restoration using two types of convector controllers. Up to 16 convectors can be connected to the Type 1 controllers. Type 2 convectors can control up to 24 units thanks to an I/O system expansion. For this purpose, Caverion linked two convectors to one analog output from the WAGO-I/O-SYSTEM 750. “In our system, two convectors form a fixed pair that we can switch using one output on the WAGO node,” explains Jan Sierck, project manager at Caverion. Since flexibility was a cornerstone the project, the system had to be, “relatively easy to reprogram” states Sierck. The system thus delivers spatial flexibility, which is crucial for reorganization or renovation. This ensures that the building can adapt to the organizational changes requested by renters.
The 750-881 WAGO PLC takes over the everyday target-performance comparison between the desired and the actual temperatures that prevail within a single space of the office building. In office spaces, the target value is 22 °C (72 °F). If this temperature is exceeded by one degree Kelvin (1.8 °F), then the heat controller is triggered and the hot water valve is controlled using PWM (pulse width modulation) signals. The WAGO-I/O-SYSTEM simultaneously controls the fan speed in the convector units as well. The setting range is determined using a 0–10 V analog signal.
Scalable Control Technology
The reason for selecting two different, scalable expansion stages from the WAGO-I/O-SYSTEM was, according to Sierck, in order to create the smallest divisible room spaces. Sought to cut down on commas: In fact, the spaces can be minimized to just one grid space when a copy room and small storage area need to be created on a corridor. In light of extremely flexible spaces that lend themselves to reconfiguration and the possibilities for programming the controllers, it was unclear at the project’s beginning where the technology itself would be situated.
The original design called for the installation of the WAGO-I/O-SYSTEM in distribution boxes, which would then be recessed into the floors. “The idea arose in the project team, born out of the desire for flexibility, to locate the control technology directly at the convectors. This was easily achievable using WAGO components,” explains Sierck about the system selection. “The I/O system can also be used for communication. We are already underway with ETHERNET, and can collect all other communication systems like KNX, DALI and BACnet using interfaces and transmit data in packets to the building control technology.
In addition to the wall convectors, Caverion also designed structurally identical ceiling convectors for interior floor spaces. The control technology for these is located in one of two substations on each floor. The fire dampers are also switched using these controllers. The WAGO-I/O-SYSTEM 750 collects data from more than 100 dampers per story and transmits this data in bundled units to the building control system via ETHERNET.
“We created significant savings in the wiring by using this communication structure,” states Sierck. In addition to the advantages of shortened cable paths that reduced the costs for conductors and infrastructure systems, the minimized spatial requirements also reduced the thermal load thanks to just two ETHERNET circuits running through each floor. Here ETHERNET forms the foundation for decentralized, intelligent automation without limiting data availability. The WAGO-I/O-SYSTEM 750 enables virtually any combination of digital and analog signals, as well as the combination of more complex subsystems into larger aggregates. “By ordering just a few more I/O modules, we can easily expand at any time in the future,” summarizes Sierck. The project at Kapstadtring 2 is not yet complete. Since the building’s spaces are tailored to the company that rents them, there will always be adjustments that ultimately affect the building technology.
- The WAGO-I/O-SYSTEM enables any combination of digital and analog signals.
- Future expansions can also be easily implemented.
- The flexible programming options maximize the configuration possibilities and uses for the spaces.
Text: Stephan Lampe, WAGO