Issue link: https://cp.revolio.com/i/809568
6 | THE DATA CENTER JOURNAL www.datacenterjournal.com down for IR viewing every six months per traditional standards." Back Me up Continuing the power theme, another point of interest is battery technology. Energy storage is a chief limiter of innovation; because storing a lot of energy safely, efficiently and accessibly in a small volume is diffi- cult, it tends to have a short shelf life. Some developments are taking place on the battery front, however. Spears notes that although nothing is brand new, lithium-ion batteries are a hot area. "Many UPS vendors are offering lithium solutions because there is a heightened level of interest with cli- ents today. e safest lithium batter- ies are a little heavier and larger than those used for phones and laptops, but they boast benefits when it comes to thermal performance, battery cycle life and maximizing power capacity." Moreover, costs for this technology are falling, although they still have yet to come close to those of traditional lead-acid technology. Other energy-storage technolo- gies for short-term use include su- percapacitors (which operate electri- cally) and flywheels (which operate mechanically). e latter technology has been around for a while, but the former is beginning to play a larger role in the data center. "Offering improved safety features, supercapaci- tors now provide a better backup time of 30–60 seconds," Spears observed. "at's generally a good amount of time for hospitals and other facili- ties that have generators on standby and don't need as much backup time. ey are still more expensive than flywheels, but they are preferred as an electrical rather than mechanical storage device." For long-term energy storage, an interesting development is the increasing replacement of diesel fuel with natural gas to power generators. Spears noted, "ere was concern that natural gas wouldn't work as well as diesel with difficult loads such as UPSs, or in the face of weather events such as earthquakes, but those con- cerns have been mitigated in modern large generator designs." is change could also yield environmental ben- efits if natural gas is consumed more cleanly than diesel. Stay cool, Man Although necessary, cooling has been a downer for the data center's reputation because it's a major con- tributor to high power usage effec- tiveness (PUE). e growth in free cooling, including ASHRAE's updated guidelines that make this approach a possibility almost anywhere in the U.S., seems to resolve the issue, but not everyone is buying in. "It's true that free cooling has been an on- again/off-again topic in the industry," said Spears. "Based on what we hear, it seems to be a divided set of design- ers and end users. Some are tradition- al, while others say free cooling and other new techniques are worth the investment. ose with the traditional perspective don't want to risk the data center being too warm, so they stay with traditional AC solutions even if they're a bit more expensive. Coloca- tion data centers also have customers who may be reluctant to change." On the other side of the is- sue, some designers "feel they can run data center efficiently at higher temperature and reap big cost savings. ere is a learning curve, but once it's tweaked, they do seem to have a lot of success with this approach." ASHRAE's guidelines have no doubt helped in this regard, permitting higher operating temperatures for certain types of equipment. But among pundits today, cooling may be falling behind server inefficiency as the most vilified energy consumer. Still, few businesses or consumers are reducing their demand for IT ser- vices, so data center operators face a tough mix of demands. rack 'eM up Some server racks may still be nothing more than metal frames that just hold equipment in place, but data center operators have a num- For long-term energy storage, an interesting development is the increasing replacement of diesel fuel with natural gas to power generators. Spears noted, "There was concern that natural gas wouldn't work as well as diesel with difficult loads such as UPSs, or in the face of weather events such as earthquakes, but those concerns have been mitigated in modern large generator designs."