Green doesn't mean expensive
Most organizations assume the costs of going green are extravagant, but Gopani says that's a misconception. "We have seen a payback of three to four years for most of our green initiatives around 60%-70% of the time," he says.
However, Gopani clarifies that certain green initiatives with long-term payback have to be evaluated in detail before going in for them. Many times, initiatives with a longer payback provide more benefits over a much extended time frame. In addition, a green technology initiative's focus should also be on maximizing efficiency through reduction of losses.
Get the planning right
When building a green data center, extensive planning is the most crucial factor. It was no different for Wipro Infotech's Greater Noida site, which has more than 40,000 square feet of data center space. The data center's planning and design were undertaken by Wipro Infotech's data center design team and Wipro Infrastructure Engineering's EcoEnergy group.
Gopani and his teams conducted exclusive planning for almost four months before selecting the various data center solutions. Power and cooling were identified as the primary areas for green technology deployment, increasing efficiency and cost savings.
Reduce electrical losses
Since the maximum amount of electrical losses happen at the UPS, this was the first focus area during the design stage. Highly efficient IGBT-based UPS systems, which are 4% to 5% more energy efficient than traditional UPS systems, are in use at the data center. Since an N+N design is used for the UPS system, units that provide the highest efficiency while working between 25% to 50% load have been deployed.
Although the Greater Noida data center has not yet been assessed for the power usage effectiveness (PUE) ratio, Gopani and his team are confident. "We plan to bring down the PUE by 15%, as compared to a normal data center's PUE, which is in the range of 2 to 2.2," Gopani says.
Cooling is yet another major aspect to be optimized when striving for a green data center design. Hence, Wipro Infotech implemented liquid-based cooling for its server racks.
The liquid cooling system in use at Wipro Infotech's data center is claimed to be 35% more efficient than conventional air cooling systems. In this system, chiller pipes are run on the data center perimeter. Precision air handling units connected to these chiller pipes help cool the servers. "On the refrigerant front we have standardized on the use of R410A or R407C for all our precision air conditioners, which is a zero ODP [ozone depletion potential] refrigerant system," Gopani says.
Significant amounts of fresh water are required for such liquid cooling models for the data center. At present, despite the data center not being fully occupied, the liquid cooling system consumes around 1.5 million liters of fresh water a month. This requirement is bound to increase once all the racks are full. In anticipation of this demand, Wipro Infotech has implemented a sewage treatment plant (STP) to recycle waste water used in the data center. The recycled water from the STP is used for cooling tower operations, significantly reducing fresh water requirements. This measure is estimated to bring down the data center's fresh water requirement by almost 6 million liters per month.
Wipro Infotech's next green step on the cooling front is the use of variable frequency drive-based chillers, precision air conditioning and air handling units. These units operate at higher efficiency under part load.
Gopani stresses the importance of properly segregating utility areas according to the need for cooling. A data center typically has multiple utility areas like UPS rooms, battery rooms, seating space, distribution room and fire suppression room. "Each utility area has a different cooling requirement. Typically, standard cooling is implemented for all the utility areas, and the cooling requirement goes up. Instead, if you segregate each utility area properly and understand the cooling requirement of each room, that can bring down the cooling requirements further," Gopani points out. This is supplemented by the use of free cooling options for utility areas during the winter. "In Greater Noida, during winter we have outside temperatures below 15 degree celsius. So we use special air handling units on free mode to cool utility areas. This helps reduce our total cooling requirement by 10% during winters," Gopani says.
Other green technologies
Wipro Infotech's data center building is oriented in the north-south direction to minimize the heat radiation from sun. This is supplemented by the use of aerated autoclaved concrete blocks for walls, which has better thermal insulation than traditional brick walls.
On the fire suppression front, the Greater Noida data center uses a NOVEC 1230-based fire suppression system, as it complies with the Kyoto protocol. NOVEC 1230 has several eco benefits like a non-ozone-depleting nature, five-day atmospheric life span and a global warming potential of 1.
Gopani says he expects approximately 30% savings on data center cooling due to liquid-based cooling. Apart from that, the use of the STP will substantially bring down the fresh water requirement.
From the corporate viewpoint, the new data center will significantly reduce Wipro Infotech's carbon footprint. "We also expect at least 4-5% savings on electricity consumption because of our high-efficient UPS systems," Gopani says.
The path forward
Hot aisle-cold aisle isolation in server hall area is under consideration for the data center. This ensures that cold air does not mix with hot air, thus improving the data center's overall cooling efficiency by approximately 10%.
Since the data center can host 450 racks, multiple hot aisles and cold aisles will be in place. Each row of racks will have its own hot and cold aisle.