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No. 2393:
Greener Computing

by Andrew Boyd

Today, greener computing. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

Computers use energy. So much energy, it's becoming a problem. A big problem. A desktop computer uses about as much energy as fifty fluorescent light bulbs. The problem's magnified in data centers.


Data centers are where businesses keep their computers. They're impressive to look at. Stacks of computers mounted in racks — lights flashing on the front, a tangle of wires sticking out the back. Heavy, locked doors guard room access. Energy is vital for data centers. If they can't get enough, business comes to a halt. At times their need for power strains the nation's power grid.

Data centers use so much energy that for every two dollars spent on computer equipment, businesses spend one dollar powering and cooling that equipment. And the problem's only getting worse. The cost of energy's going up; the cost of computers, down. In the next few years, we expect to spend more money running computers than buying them.

So data centers are now in the spotlight. Businesses want to reduce costs. Even the Environmental Protection Agency's gotten involved. What can we do to reduce energy consumption?

There are really two parts to the story. First, there's the energy needed to run computers. But just because they're running doesn't mean they're doing anything useful. A lot of their time is spent sitting idle. So we can save energy by using the computers we've got more efficiently. That's a systems engineering problem.

But there's also the problem of heat. Computers produce heat — a lot of it. If you have one under your desk, you know what I'm talking about. There's a fan to carry away heat. Without it, your computer would get too hot to work.

Close to half of the energy used by data centers goes toward climate control. Computers like to operate at about seventy degrees and fifty percent relative humidity. You can feel the change when you walk into a data center. You hear it, too, as fans blast air on the machinery. Energy's saved when all the pieces work together — from the choice of equipment to the placement of the fans. It's all about the system.

For a long time data centers didn't get much attention. Nor did the engineers who ran them. But that changed. By 2008 the demand for people with data center experience outpaced the supply. Salaries shot up. And once-invisible engineers were taken from the back room and moved front and center. Working with whole systems isn't always as sexy as designing a new computer chip or writing mind-bending programs. But systems engineers are vital. And they'll only become more so in the future.

Said one engineer who'd worked in data centers for many years, "We were seen as sheet-metal jockeys. But now we have a chance to change the world for the better, using engineering and basic science." Isn't that a dream we should all be so lucky to achieve.

I'm Andy Boyd at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

For related episodes, see High Heat Flux in JapanHeat TransferMore Than One Computer, and Operations Research.


I am greatly indebted to Professor Natarajan Guatam, Department of Industrial and Systems Engineering at Texas A&M University, for bringing data center power consumption to my attention.

The quote in the essay is taken from S. Lohr, Demand for Data Puts Engineers in Spotlight. New York Times, June 17, 2008.

Photo courtesy of Wikipedia.