Green Right Down to the Wiring and Cabling
February 1, 2009
The energy and natural resources that a data center consumes is very significant, and more facilities than ever are being built today. Using criteria that encompass a whole building approach, LEED focuses on five areas: sustainable site development, water savings, energy efficiency, materials selection, and indoor air quality.
The U.S. Green Building Council (USGBC), developed its LEED green building certification ratings system to give companies and builders a set of guidelines to use for designing and constructing sustainable building projects, is itself a coalition of building industry leaders working to promote buildings that are environmentally responsible, profitable and healthy places to work.
While actual LEED accreditation may be very difficult to define or achieve for a data center, the goal of any project is to try reducing the carbon footprint of the facility being built. As part of that team, the telecommunications distribution designer needs to look at ways the cabling infrastructure can be part of greening the data center. Of the five LEED criteria, the telecommunications distribution designers influences material selection most. This influence can expand to include the deployment and design of the materials in that cabling infrastructure. The designer can research manufacturers and how they produce the materials, recycle old or abandoned cabling, look into design concepts that can reduce the amount of raw materials needed to build the infrastructure, and ways to reuse existing infrastructure during future technology refresh cycles.
Product Manufacturing ProcessWhen looking at design concepts that can reduce the cabling materials in the data center, placing switches in the row with servers is one interesting idea. This concept can alleviate the need for raw material in two ways. First, by deploying switches in the row with servers, the cabling that is run from the MDA to each row is only fiber optic cable, not the multitude of copper cables needed to run to the HDA when switches resided there. (Remember those 100,000 feet (ft) of cable per row). The fiber cable itself uses less raw material than the copper cable, and much less of it is needed. One multi-strand strand fiber optic cable can provide all the backbone the in-row switches will need. 200 feet of multi-strand fiber optic cable can replace 100,000 feet of CAT 6 copper cabling.
Taken one step further, once the switches are within the row, patches can run directly from the switch to the server equipment. The TIA 942 standard allows for direct equipment-to-equipment connections via patch cords up to 15 meters (49 ft). By laying out equipment to meet this criterion, connections can be deployed on an as needed basis without deploying infrastructure between patch panels and then adding a patch cord at either end. This results in further material reduction.
In addition, when there is a technology refresh, the patch could be replaced as needed if connectivity requirements changed. And better yet, those patch cords that were removed could be reused in other locations.
The designer can also to look into higher bandwidth cables. Technology refresh is an unavoidable reality in the data center world. With new equipment comes faster processing speed and higher bandwidth requirements. If during the original design, only minimal headroom was taken into account for those applications, then the increased requirement from the new equipment may render the cable plant obsolete. The result would be re-cabling the data center with the higher bandwidth cabling. The old cabling might be recycled but could wind up in a landfill. Reasonable headroom in the design can allow data center cabling to survive more technology refreshes.
Furthermore, the use of fiber optic cables can reduce the amount of cabling and insulation materials required to build out a data center. First off, a fiber optic cable uses much less insulation material than copper cable because the transmission media is light waves and not electricity (see figure 2).
Light traveling along a fiber optic cable is not susceptible to electromagnetic interference like the electrical signals and does not need increased isolation from outside influences. Fiber optic cables have overall higher bandwidth, allowing the designer to use less fiber optic cables as compared to copper. This approach aligns itself with distributing the network switches into server rows and only having fiber optic cable connecting the row to the MDA. This will have a large impact on the overall length of cable deployed in the Data Center.
While many factors can influence the carbon footprint of a facility, one of the main ways a telecommunications distribution designer can influence the level of green in their design is material selection, limitation and reuse. The designer can look into the manufacturers and how they produce the materials, recycle old or abandoned cabling and look into design concepts that can reduce the amount of raw materials needed to build the data center infrastructure. With any aspect of environmentally friendly approaches, a little planning can go a long way.