Beating datacentre heat, on the cheap
Cut energy usage in the datacentre by turning up the heat
By Ted Samson, Infoworld | InfoWorld | Published: 01:00, 30 July 2007
In the datacentre, admins are feeling the heat. Business-critical hardware must remain properly cooled, but the energy bills seem to soar exponentially as the temperature rises.
Fortunately, even the most frugal and financially-strapped organisations have ways to cut their AC bills without having to perform an entire IT-operations overhaul. The following are a few tips for trimming not only some expense from your cooling bills, but as a result, shrinking your organisation’s environmental footprint in the process.
1. Fight heat with heat. According to Dave Douglas, Sun’s vice president of eco-responsibility, increasing the set point temperature in your datacentre by just one measly degree can reduce energy consumption by four to five percent. Raising the set point from 20C to 22C could save 15 percent to 20 percent of the cooling energy, according to Douglas, “while still keeping air inlet temperatures well within computer manufacturer specifications.”
In fact, the American Society of Heating, Refrigerating and Air-Conditioning Engineers suggests setting the temperature in a modern data centre at 25.5 degrees, which reaps even more savings.
2. Plug holes in the raised floor. Plugging those holes in the floor is a widely recommended best practice. Leaks can result in cool air escaping, as well as hot spots. Holes and leaks can crop up in various places. One of the more common culprits are the cable holes under racks and cabinets. Robert McFarlane, president of the Interport division at Shen Milsom Wilke, recommends plugging those holes with either a do-it-yourself sealant, made from Masonite and duct tape, for example, or using a commercial product. Placing blanking panels on all unused space in front of a rack call also promote efficient cooling.
3. Enter the thermal zone. Experts such as Digital Realty’s vice president of Engineering Jim Smith recommend setting up hot and cool aisles in the datacentre. In this kind of layout, each aisle between rows of server racks is bounded with either just hot-air outlets or cool-air intakes. The goal is to isolate and extract heat before it mixes with cold air. Use strip curtains to enhance the separation by blocking open space above the racks.
4. Pull some plugs. Hopefully you have a way of knowing which machines in your datacentre are actually being utilised. If not, performing an inventory is always a good idea. Once you’ve done that and determine which ones are running at zero percent utilisation, unplug them, suggests Douglas: “If there is a problem [and] someone complains about the system being unavailable, turn it back on.” You will see immediate power and cooling savings.
5. Harness the elements. Air- and water-side economisers, or a combination thereof, can help deliver efficient, inexpensive cooling in the right environments, according to Amory Lovins, CEO of the Rocky Mountain Institute. He told SearchData centre.com: “An air-side economiser is very cheap in capital cost and uses essentially no energy, just a tiny bit for controls. Water-side economiser, evaporative cooling with a cooling tower, and heat exchanges in your chilled water loop, [costs] US$100 (£49.39) per tonne. If you design it very well, it gives you 100 or even 125 units of coefficient performance.”
These tips are, of course, just starting-off points, but they’re well worth trying. Not only might they help you achieve some of the cost-saving benefits of a greener datacentre, but, hey, all the cool IT pros are doing it.