Data Center Cooling Efficiency

Craig Watkins
Product Manager,
Rack & Cooling Solutions
Tripp Lite

Combining a hot-aisle/cold-aisle configuration with SmartRack thermal duct rack enclosures (SR42UBTD) and close-coupled, row-based air conditioning units (SRCOOL33K) creates a highly efficient data center cooling solution.

Energy efficiency in the data center used to be an afterthought, if it was on the radar at all. "It made sense at the time," says Craig Watkins, product manager for rack and cooling solutions at Tripp Lite. "If your data center felt uncomfortably cold, people were impressed. It was considered a sign that you were doing a good job keeping servers from overheating. Rack densities were lower, electricity was cheaper and nobody was paying attention to the electric bill."

Today, data center managers need to keep a close eye on energy costs. According to the Uptime Institute's 2011 Data Center Survey, 97% of respondents said reducing energy use was either "somewhat" or "very" important, and 87% said the primary motivation was cost reduction. An Uptime Institute study also found that up to 70% of data center energy use is for cooling and air handling, so increasing cooling efficiency is vital to reducing costs. "Start with the low-hanging fruit," advises Watkins. "You'll be surprised how much you can save with a few simple steps."

1. Implement Hot-Aisle/Cold-Aisle

"You don't need to keep your data center at meat locker temperatures," states Watkins. "Instead, concentrate on removing hot air from the room before it recirculates." Separating hot and cold air is the key to cooling efficiency. Start by arranging racks in rows so the fronts face each other in cold aisles and the backs face each other in hot aisles. That prevents servers from drawing in hot air from servers in the adjacent row. According to studies by TDI Data Centers, hot-aisle/cold-aisle configurations can reduce energy use up to 20%. Tripp Lite's SmartRack™ enclosures (SR42UB and SR48UB) are optimized for hot-aisle/cold-aisle.

2. Install Blanking Panels

"Blocking off unused rack spaces isn't just cosmetic," according to Watkins. "It forces cold air through your servers and prevents hot air from recirculating through the enclosure." Tripp Lite's 1U blanking panels (SR1UPANEL10 and SR1UPANEL50) snap into place without tools, saving significant installation time.

3. Organize Cables

"Tangled cables block airflow," says Watkins. "They prevent efficient cold air distribution under raised floors and cause heat to build up inside enclosures." In raised-floor environments, move cabling to overhead cable managers (SRCABLELADDER and SRCABLETRAY). Inside enclosures, use high-capacity cable managers (SRCABLEVRT3, SRCABLEDUCTVRT and SRCABLERINGVRT) to organize patch cables.

4. Replace Inefficient UPS Systems

"Removing unnecessary heat sources helps cool the room," advises Watkins. Replace traditional on-line UPS systems with energy-saving SmartOnline™ models to increase efficiency and reduce heat output, especially where redundant UPS systems operate below full capacity.

5. Use Close-Coupled Cooling

Gartner Group reports that close-coupled cooling increases efficiency compared to traditional perimeter and/or raised floor systems. "Close-coupled cooling allows you to focus cooling where it's needed most without lowering the temperature of the entire room," says Watkins. The modular nature of close-coupled cooling also allows data center managers to quickly reconfigure cooling to handle new equipment or overheating racks.

Tripp Lite's close-coupled cooling solutions are completely self-contained and can be installed by IT staff without costly contractors, plumbing, piping, special ductwork, floor drains, water tanks or extra parts. The portable SRCOOL12K provides 12,000 BTU (3.4 kW) capacity. The row-based SRCOOL33K has a standard 42U rack form factor, convenient L6-30P plug and provides 33,000 BTU (9.7 kW) capacity at costs up to 38% less per BTU than traditional designs. An innovative variable-speed, DC-inverter-driven compressor prevents disruptive inrush current, allows precise cooling adjustments and dynamically scales output to match the application, further reducing energy costs.

6. Isolate and Remove Hot Air

SmartRack™ thermal duct rack enclosures (SR42UBTD) route hot air through an overhead duct to the HVAC or CRAC return air stream. "They isolate hot air so it can't recirculate in the room," states Watkins. "Convection forces hot air up through the duct, like a chimney, and positive pressure in the room and negative pressure in the plenum increase airflow." You can also add thermal ducts to standard SmartRack™ enclosures with the SRTHERMDUCT kit.