Depending on where the customer is, the trade-off for locating data centers based on power, cooling or other factors, can, of course, be incrementally more network latency -- the delay caused by signals travelling through one or several thousands of miles of fiber, plus, possibly, another network device or two. For example, one-way transit from the data center to London or Europe adds 18 milliseconds, to the United States, about 40 milliseconds.
It's not just the heat, it's the humidity
"Dry places" aren't necessarily in cool locations. i/o Data Centers' Phoenix facility, which according to the company is one of the world's largest data centers, is located, as the facility's name suggests, in Phoenix, Arizona.
"One of the benefits of the desert is it's very dry," says Anthony Wanger, i/o President. "It's easier to remove heat in a dry environment, which makes Arizona an ideal location."
According to the company, the Phoenix data center employs a number of techniques and technologies to reduce energy consumption and improve energy efficiency.
"We are doing everything possible to be energy efficient at all of our data centers, says Wanger. "We separate cold air supply and warm air return." To get the heat away, says Wanger, "There is still no more-efficient means of moving energy than through water. Air as a liquid is much less dense and less efficient. Once we get that hot air, we dump it into a closed loop system and exchange it into an open-loop system, where we can remove the heat. We also use thermal storage. We can consume energy at night when it's sitting in the utility's inventory."
Also, says Wanger, "We have to put humidity into the air. The old way was to have a big metal halide lamp baking water. The humidification solution was to fire up a heat lamp and phase-transition it to humidity. Now we use a process called ultrasonic humidification, which uses high-frequency electronic signals to break water surface tension and dissipate cool water vapor into the air -- this takes about 1/50th the amount of energy."