How HP Enterprise Services Cools Its Data Centers
HP Enterprise Services, in doubling the size of one of the data centers it got in the EDS deal to more than 400,000 square feet, put in a host of ecofriendly features. HP put a reflective material on the roof to deflect heat from the sun, and installed a backup cooling system that will save the company several million dollars, Kettler said. In addition, a chilled water storage tank that can hold up to 800,000 gallons lets the facility run for up to 8 hours without having to use the chiller/cooling plant, he said. The company also made other changes, including replacing many of the T connections in the water pipes with new pipes that run at 45-degree angles, which reduces the amount of energy needed to move the water through the pipes. It also reduced the environmental impact of the construction and operation of the city, including setting up a water retention program through the use of trees and shrubs, he said.HP Enterprise Services also is turning a building initially meant to house a distribution center into a data center. The Wynyard data center is in Newcastle, England, next to the North Sea, and HP is using the frigid coastal winds to help keep the data center cool, a technique called free air cooling. "It's cold and windy in northeast England," Kettler said. "We can take advantage of that." The cold air outside is directed into a room inside the building, where it's mixed with air from inside the facility. The cool air is then fed into the cold aisle flooring in the data center and moved through the equipment, and the warmer air is exhausted through the back, Kettler said. Eventually some of the warmer air is released outside, while the rest is reused. The result is energy savings of about 40 percent compared with typical data centers, Kettler said. It also helps gives the Wynyard a PUE score of 1.16, he said. The free air cooling system takes advantage of outdoor temperatures about 97 percent of the year, enabling the data center to forgo using the chillers. If the weather outside is too hot, auxiliary chillers are brought online. Other green features include angling light inside the data center at a 45 degree angle to the servers, which improves the lighting. The use of light-colored racks and white paint on the walls also helps reduce the amount of lighting needed, saving about $7 million a year, Kettler said. HP also is putting reflective material on the Wynyard building's roof, and is capturing rainwater to be used for landscaping and fire fighting purposes, he said. In addition, 10 percent of the energy used in the data center comes from wind-powered sources. The result of all this is the reduction of megawatt hours from 27,5000 to 20,000 per year, and reduction of CO2 production from 17,500 to 8,770 metric tons, giving a smaller carbon footprint.
The building now has a PUE (power usage effectiveness) score of 1.6 to 1.7, Kettler said. The PUE metric was created in 2007 by the Green Grid consortium to measure the energy efficiency of a data center. The score is calculated by dividing the total amount of energy in the data center and dividing it by the power that reaches the IT equipment. The closer to 1 the score is, the better. Typically, data centers in the 1990s would have had a score of 2.0 or more, Kettler said.