BY WESLEY CARE, EIT
You probably checked your email today. Then maybe you updated your social network status and looked at some friends’ photos, or watched a humorous video. After that, you might have scheduled a credit card payment, made a bank account transfer, and adjusted your stock portfolio. Often called “cloud computing,” doing these things makes you a part of the explosion of interconnectedness which will define an era. You can access almost anything from almost anywhere, with the necessary software, data storage, and computing power residing somewhere in “the cloud.”
But it all has a physical location, and this massive wave of information brings with it a surge in energy consumption–every online operation requires a specialized computer, called a server, to process it. For the most part, these servers are kept at nondescript buildings called data centers, which are warehouses specifically designed to handle the machinery of our high-tech lifestyles. These facilities are built in terms of megawatts, not kilowatts, of capacity, and operate 24/7. Jonathan G. Koomey, a Stanford research fellow, estimated for the New York Times that data centers in the United States used about 76 billion kilowatt-hours in 2010—about 2 percent of the total electricity consumed in the country. For comparison, the U.S. Energy Information Administration data shows that the entire state of Arizona consumed almost 73 billion kilowatt-hours of electricity that year. The average residential utility customer consumes about 11,500 kilowatt-hours per year.
Don’t close your web browser just yet–the industry is beginning to respond. Thankfully, being environmentally conscious can actually raise corporate profits, because saving energy (lots of it) means saving money. The main energy users are in two areas: the servers themselves, and the air conditioning required to keep the servers in their operational temperature range, because every watt used by a server generates heat.
Server manufacturers have made saving energy easier in several ways. Their equipment is smaller and more efficient, meaning the same computation process uses less energy than it used to. New equipment can also handle very different space temperatures. Data centers used to be kept very cold, causing workers to wear jackets year-round. Now, the servers are designed to take in much warmer air–78 degrees or higher in some cases–which drastically cuts the first cost and operating cost of the air conditioning equipment required.
Data Centers Design
Data center design is improving as well. Most data centers cool the air with giant air conditioning units, and constantly cycle air through the server room. Today, many data centers can automatically turn off the air conditioning and switch to outside air (just like opening a window when it’s nice outside) to cool the servers when the conditions are right. Some of the latest designs are using adiabatic cooling, which takes advantage of the cooling effect of evaporating water (it’s the same reason you feel cold getting out of the pool when it’s 90 degrees outside). Even in Phoenix, a data center can operate thousands of hours per year using only outside air and evaporation. Additional savings come from limiting the amount of air provided and when. While most data centers operate 24 hours a day, the servers are not usually utilized at 100 percent. Newer systems automatically respond by providing less air whenever possible, saving energy on the fans and cooling requirements.
Data center engineers are always seeking ways to be more efficient, and are getting more incentives to do so. The U.S. Green Building Council’s LEED program is being updated to include paths for data centers. Data centers also informally compete with one another for Power Usage Effectiveness (PUE), and engineers are often selected based on their abilities to produce a competitive facility.
Cloud technology will continue to grow–and while you are engaging in eco-friendly practices, rest assured that many of the online services are reviewing their energy footprints as well.
Wesley Care, EIT, is a Mechanical Project Engineer at Energy Systems Design, Inc., an MPE Consulting Engineering firm in Scottsdale, AZ. ESD has worked in-depth on cutting-edge data center design, and also specializes in high-efficiency systems for commercial and municipal buildings, universities, and laboratories.