Each ACRC100 is delivered with two L6-20 power whips, although only one is required. The other can be used to provide redundant power to the unit. Also, the ACRC100's power draw is low enough to be reliably administered through a large UPS system, providing cooling even during a power outage. Although the roof-mounted chiller is still subject to power loss, the cold water in the piping and CDU should be enough to maintain a high level of cooling output and heat rejection for quite some time.

Make no mistake, the ACRC100s pump out an amazing amount of cold air. Even a single unit could take care of a small server room all by itself. In the three months I've been running four ACRC100s, they've proven reliable and very cost-effective.

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InfraStruXureNetworkAir PA
At the low end of APC's air conditioning line are the NetworkAir PA units. I tested the larger of the two models, the PA4000. This unit is essentially a smaller version of the ACSC100, but in a portable package. Looking like a Shop-Vac on steroids, the PA4000 adheres to the same basic air-handling principles as the ACSC100, requiring that a single intake and exhaust duct be run to the plenum space. The management application (an older version of the software for the SC and RC units), however, is more limited; it allows for simple monitoring and basic configuration of notifications but doesn't permit changes to the unit's set points or other cooling parameters.

The NetworkAir PA can find a home anywhere that needs highly focused cooling or as a stopgap measure during datacenter AC maintenance. Given that the SC and RC units ride the edge of performance and that the failure of a single unit can quickly become a big problem, having the ability to rapidly deploy cooling to specific locations is a great insurance policy.

In my lab tests, it became clear that the NetworkAir PA is best suited for small rooms. With a maximum cooling output of 4kW, the PA just couldn't keep up with the cooling needs of the lab on its own, although it certainly tried. It's also not terribly useful in high-temperature situations. Although it can supply air roughly 20 degrees cooler than the intake air temperature, that doesn't help if the room's already 95 degrees Fahrenheit. For small spaces, the PA might fit the bill, but for anything beyond a single-rack server room, it's not a solution by itself.

The APC InfraStruXure InRow SC, InRow RC, and NetworkAir PA all deliver on the promise of effectively cooling only what needs cooling, while reducing energy costs. The air-cooling SC and water-cooling RC units can be integrated into traditional datacenters or deployed as the only cooling solutions in the room. The portable PA is a viable solution for small spaces and a great unit to have around for emergency backup. In-row cooling solutions have been widely regarded as a curiosity, but as datacenters become denser and energy bills rise, it's becoming clear that the days of traditional datacenter AC are numbered.