Emerson Network Power rolled out a “free cooling chiller” for small and medium size data centers, which operates in both the typical mechanical air conditioning mode and the free cooling mode.

Free cooling is when water used in air conditioning systems is cooled by cool weather outside. There is another approach to free cooling, which is simply pulling outside air into the data center through massive louvers and fans on a building’s wall.

The second method, called air-side economization, is less effective than the water-side economization method Emerson’s new chiller uses, according to the vendor. The company sells both kinds of economization solutions.

One of the typical air-side system challenges is having to build ductwork to bring air to the IT floor, according to an Emerson white paper on economizers. This is especially difficult if owners of an existing facility want to add free cooling.

An air-side economizer can also potentially run for a shorter period of time without needing supplemental humidification. The colder the air, the dryer it is, so outside air pulled inside during cold weather often needs to have moisture added to it.

Outside air can also be more humid than necessary and can carry dust and pollen, in which case operators need special sensors to minimize filter maintenance. Outside air can also create mildew.

Overall, using an air-side economizer requires sophisticated controls to make sure the air’s temperature and humidity are at appropriate levels, which can be costly.

The new chiller Emerson is offering, Liebert HPC-S Chiller, can supply chilled water at fairly high outside air temperatures (up to 78F), as well as below 0F. This maximizes the amount of time an operator can get chilled water without running mechanical air conditioning.

The product includes Emerson’s Liebert iCOM control system which switches to free cooling mode quickly when weather is appropriate. It can be networked to control a group of chillers without another building automation system.

Ideally, Emerson would like operators to bundle the chiller with its in-row Liebert CRV system. It is installed between IT racks and uses chilled water to create cold air it pushes to those racks.

Emerson also recommends using the two solutions together with its cold-aisle containment solutions to further optimize for efficiency, promising a potential “mechanical” PUE of 1.2. PUE stands for Power Utilization Effectiveness.

John Schneider, VP and general manager of thermal management at Emerson, said, “The Liebert HPC-S Chiller delivers up to 40% annual energy savings in data center applications over traditional products.”