Moreover, the building's automation system contributes to the facility's energy efficiency, automatically responding to changing conditions. For example, it can shift to free-cooling mode -- drawing on free outside air to cool the IT equipment -- based on atmospheric changes. It can also adjust internal temperatures, including the raised floor areas, based on time of day or customer-defined thresholds.
Digital Realty Trust found other ways to reduce waste with this new datacenter facility. For example, the external and ancillary lighting are all powered by photovoltaic cells located on the roof. Fifty-three percent of the site was constructed from recycled material. Furthermore, the company preserved the surrounding indigenous flora and fauna, and irrigation of the Welwyn facility's landscaping is provided through a rainwater-harvesting system that also supports interior applications.
All these techniques add up to significant savings and environmental benefits. The Welwyn facility is expected to enjoy annual energy savings of 48.2 million kWh, cost savings of $4.7 million, and an annual CO2 emission reduction of 20,090 tons.