Moreover, the unit ratchets down its cooling activities during idle times, saving even more money. All told, the cost-cutting benefits of localized cooling are quickly proving convincing, so much so that Gartner predicts in-rack and in-row cooling will become the predominant cooling method for the datacenter by 2011.

Modular air conditioning

For enterprises considering localized cooling, APC’s in-row units are available in both air- and water-cooled models that provide from 8kW to 80kW of cooling output. The smaller APC units -- the ACRC100 and the ACSC100 -- are the same height and depth of a standard 42U rack, but half the width. The company’s larger ACRP series retains the full 42U-rack form factor but pushes out far more air than the smaller units do.

Power and cooling giant Leibert is another vendor offering localized cooling solutions. Its XD series in-row and spot-cooling systems are similar in form and function to their APC counterparts. Leibert also offers units that mount on top of server racks, drawing hot air up and out. Both APC and Leibert have rear-mounted rack ventilation and cooling units that exhaust hot air into the plenum or cool the air before passing it back into the room.

The modularity of these systems translates to significant startup savings. Whereas whole-room solutions must be sized for anticipated growth, localized cooling units can be deployed as needed. A large room that starts out only 30 percent utilized will require only 30 percent of projected full-room cooling hardware upon initial deployment.

There are downsides to these units, to be sure. The water-cooled systems require much more piping than centralized units do, and water pipes must be within the ceiling or floor of the room. The air-cooled units can place large heat loads into the plenum above the datacenter, resulting in airflow and heat exhaust problems. Moreover, because these solutions are built to provide just enough just-in-time cooling, the failure of a single unit can be taxing. Either way, whether you’re rolling out a new energy-efficient datacenter or retrofitting one already in place, a comprehensive understanding of your building’s environmental systems and the expected heat load of the datacenter itself is required before implementing any localized cooling solutions.

Cool to the core

For some enterprises, individual high-load servers bring the kind of heat worthy of a more granular approach to cooling. For such instances, several vendors are making waves with solutions that bring a chill even closer than nearby racks: in-chassis cooling.

SprayCool’s M-Cool is a water-cooling solution that captures heat directly from the CPUs and directs it through a cooling system built into the rack. The heat is then pushed through a water loop to completely remove the heat from both rack and room. Cooligy is another vendor offering a similar in-chassis water-cooling solution. SprayCool’s G Series takes the direct approach to cooling a step further, functioning like a car wash for blade chassis, spraying nonconductive cooling liquid through the server to reduce heat load.