Mar 1, 2015 - Building
The Best Climate for Maintaining a Well-Informed Posterity
The external facade of the building, finished just last year, is unprepossessing; however, its contents are priceless. Six million volumes of documents, eyewitness accounts in the form of photographs and film will be transferred into the storage archive for the Prussian Cultural Heritage Foundation. Once the move is complete and the artifacts have been collected from their diverse locations in Berlin, they will be stored in 36,000 meters of shelving: a gift of historical knowledge to posterity. A constant interior temperature is necessary to preserve the materials. The WAGO-I/O-SYSTEM 750 plays a key role in controlling air volumes, temperatures, and humidity.
20 degrees Celsius, 50 percent relative humidity, and UV-free light are the three essential core elements that create the best preservation environment for books, magazines, and newspapers. Slides, negatives, vintage photographic prints, and microfilm prefer a somewhat cooler and drier climate. For this purpose, nine complete air conditioning systems, six large and three small chillers, twelve smaller exhaust and smoke extraction systems, and other environmental systems, are now in use in new building. Located in the countryside near Berlin-Friedrichshagen, the main building extends 126 by 68 meters. To understand the extent that this technology covers, a glance at the roof of the closed stacks makes everything impressively clear: the shining surface of the main HVAC generator dominates the view.
Among the most crucial requirements for the automation technology, implemented by Caverion, are availability, high energy efficiency, and a narrow tolerance range between setpoint and actual values for controlling the indoor climate. The ventilation control for the storage archive is executed using the so-called negative position monitoring. Accordingly, the variable volume flow regulator located at the least favorable spot in the duct determines how much upstream pressure the ventilation system must supply in order that the volume flow can still be controlled by the damper flaps in the duct. If the system generates more pressure than is necessary, the energy efficiency drops. “The higher the pressure, the faster the fans have to rotate” explains Andreas Erdmann, Project Manager from Caverion’s Dresden subsidiary. In contrast, a volume flow that is too low prevents the precise control necessary for maintaining the climatic conditions within the storage facility. “If the damper flaps are open to around 85%, then virtually nothing more can be changed in the volume flow,” explains Michael Schilbach, an I&C designer who works for Ridder und Meyn in Berlin.
Savings by Reducing Air Volume Flows
196 variable volume flow regulators are incorporated in the ventilation network. The reason for the high number of regulators is that the closer the volume flow is adapted to actual needs, the more favorable this is in relation to energy expenditures. Savings are gained on the one hand through the lower rotational speed of the fan motors, and on the other due to the smaller volume of air that requires cooling or heating. “Every time the frequency-controlled fans prevent an unnecessary cubic meter of air from entering, the facility saves money. The fans associated with the ventilation system have the greatest effect on the costs related to total climate control in a building. The impact is even larger than that of heating or air conditioning,” Schilbach adds to his list of reasons.
Additional savings with regard to the efficient use of resources can be deduced from the network structure. The building automation (BA) in the Berlin storage archive communicates generally via BACnet/IP, however, there is no separate BA network. Due to a sophisticated network structure, the BA components communicate with each other using the IT lines. “This is something exceptional: we are using one single wiring network to run two completely different systems,” states Erdmann. For Sascha Beyer, programmer and systems commissioner at Caverion, this topology represents the future of building automation. According to him, the communication system of tomorrow will only function trouble free, “if we configure everything rationally.” Beyer is referring to the BBMD functionality available in the WAGOI/O-SYSTEM 750. This “BACnet Broadcast Management Device” prevents omnidirectional communication in the form of broadcast messages that can clog networks. In addition, the BBMD ensures that the BACnet participants are able to communicate directly with each other in a segmented network. At the control level, there are fourteen 750-831 Fieldbus Controllers and an additional four 750-830 Controllers incorporated in the network in Friedrichshagen. The controllers operate on different floors and subnetworks, yet remain in contact with each other and with higher-level control technology in Building 1 through various routers and the Berlin Research Area Information Network (BRAIN).
Everything Through One Wire
What is the advantage for building automation in using a single network for IT and BA? First, there are savings during installation. “At the moment, we are granting ourselves the luxury of improving the building with copper wiring. This is also related to sustainability,” explains Schilbach. Aside from the material costs, this development was convincing because the building owner can completely trust the competence of his IT professionals with the network. For the commissioning engineers at Beyer, their building automation experts are not always as skilled in network design. “Here in the archive building, there is only one person in charge, regardless of whether we are dealing with video or a WAGO controller.” The communication systems have to work without failures. “Even the assignment of IP addresses and BACnet IDs is consistently single-sourced,” Erdmann adds.
The entire project team currently agrees that this method does not represent an established solution. The Project Manager from Caverion is, however, convinced, “We can use the experience we have gained here and apply it directly to other projects that the State Library is developing, for example, within the context of the expansion of Building 1 in the city center.”
- The WAGO-I/O-SYSTEM 750 ensures consistent indoor climate control.
- The building automation uses the same network wiring as the IT system.
- The BBMD functionality prevents omnidirectional broadcasts from clogging the network.
Text: Stephan Lampe, WAGO