Installation of the ACSC100 is simple as far as air conditioners go. The tricky part is ensuring there's a drain within reach of the unit's condensate hose; without that piece of the puzzle, the game’s over. Assuming you have the necessary drain, just put the unit next to a heat source, fit the ducts to the ceiling panel, run them into the top of the unit, place the temperature sensor in the front of an adjacent rack, and connect the L6-20 plug to a power source -- and you're done.

Inside the ACSC100's lower rear panel is a number of data connections as well as the power supplies, the condensate drain, and the power input connections. I found the proximity of the condensate drain to power and data cabling a bit troubling, but that hasn't proven to be a problem in several months of normal operation. Power inputs are located both at the top and the bottom of the unit, so you can run the power from the floor or the ceiling without extension cabling -- a nice touch. The cutout in the bottom of the unit, however, is a bit on the small side, so running the power from below can require some cajoling of the cable. Other cutouts in the bottom of the unit can be used to route the temperature sensor cable and a network cable for access to the management interface.

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The operation of the ACSC100 and ACRC100 is inextricably tied to the rack temperature sensor, which must be placed in front of a heat source in an adjacent rack. The unit constantly monitors the temperature of intake air into the rack, adjusting the cooling output to maintain a configurable temperature set point, so placement of the sensor is of paramount importance. You'll want to place it in front of the hottest piece of gear in order to ensure that cooling levels are properly maintained. There is only the single sensor, though obviously nearby racks are affected by the cooling. In a typical installation with several ACSC100s, you'll need to do some tweaking of cooling set points and thresholds not only to get the desired cooling level throughout a row of racks, but also to get each unit working at a normal level rather than one unit running at capacity while another runs at 30 percent.

The nominal cooling output of the ACSC100 is listed at 7kW, but I've seen these units push upward of 8kW when taxed to their limit. The three fans can produce a maximum of 1,200 CFM (cubic feet per minute) of air movement, and the lowest output air temperatures I've seen were 49 degrees Fahrenheit, although 58 to 62 degrees is more typical.

I have been running three ACSC100s in a 500-square-foot datacenter for the better part of three months, and they've been performing admirably. The Web-based management application is easy to use, and it provides a wealth of information on the current status of the unit. The management console is SNMP-enabled, so integration with centralized monitoring platforms is possible. In fact, I wrote several SNMP-based plug-ins for popular network monitoring packages to bring these units into the fold.