Sabey – Oasis™ IEC provides energy-efficient rejection of data center heat
In Quincy Washington, Sabey Data Center Properties is one of six major data centers utilizing low-cost, reliable hydro electric power sustained from the nearby Columbia River.
Evaporative cooling is one of nature's fundamental methods of cooling. It is the same cooling principle that our own body uses when moisture (sweat) evaporates and cools the skin. The Munters Oasis™ Indirect Evaporative Cooling systems take advantage of evaporation to reject heat without ever adding any moisture to the data center.
By using hot aisle containment, the hot air leaving the servers is kept separate from the cool air being supplied to the servers, which allows the use of warmer supply air temperatures. This also results in hotter return air temperatures, which is an excellent situation for implementing an indirect evaporative cooling solution. With Munters Oasis™ Indirect Evaporative Coolers (IEC), the air from the data center is cooled using Munters patented Oasis™ polymer heat exchanger, often without the need for supplemental mechanical cooling or water.
On cold and cool days the Oasis™ polymer heat exchanger operates dry and simply acts as an air-to-air heat exchanger. Outside air (commonly referred to as scavenger air) indirectly cools the data center air through normal heat exchange, without the use of any water.
Once the ambient temperature rises to a certain point, the Oasis™ heat exchanger will not be able to provide enough cooling while operating in this dry mode. When this happens, water is pumped from sumps that are internal to the air handlers to spray nozzles that wet the outside surface of the Oasis™ heat exchanger tubes, coating them with a thin layer of water. During the few hours a year when the outside temperatures are too high and moist for the evaporative cooling alone, a small mechanical cooling system ("trim DX") supplements the evaporative cooling process, so that the air supplied to the data center is maintained at the right temperature. This condition, where refrigeration is required to supplement the IEC, only occurs during ambient conditions with simultaneous high heat and humidity.
To further improve the system efficiency in this supplemental cooling mode, the condenser coil of the trim DX is located in the scavenger exhaust air stream, after the heat exchanger and mist eliminator. The scavenger exhaust air, because of the evaporative cooling effect, is generally cooler than the ambient temperature whenever refrigeration is required to operate. Because the Oasis™ IEC system is a recirculating system, the data center is cooled without the introduction of outdoor air pollutants that might adversely impact the servers. Since Quincy WA is an agricultural area, air laden with dust, or smoke from burning fields would otherwise impact the data hall if a direct air-side economizer was implemented.
During integrated systems testing at full load, a peak PUE of 1.25 was recorded – a considerable achievement in such hot conditions. No data is available as to the measured annualized PUE for the entire data hall, but detailed hour-by-hour analysis predicts a partial PUE (computed based on IT and equipment cooling loads) of 1.07 using Munters system.
This proven, award winning and low energy Oasis™ IEC technology not only saves money year-round, but it reduces the following contributions to overall capital costs: the amount of mechanical cooling compared to a traditional system design, sizing of generator sets (from 2 MW to 1,5 MW), and to downsize copper wire, power switching gear, etc.
Munters Oasis™ IEC keeps the air inside the data center completely separated from the air outside. The entry of contamination (dust, smoke, etc.) from agricultural activities is minimized. Further, this highly efficient cooling system saves in annual operating costs resulting from lower power and water consumption compared to conventional water-cooled chiller systems.
"Munters Oasis™ Indirect Evaporative Cooling systems have exceeded our expectations. We’ve been very satisfied with both the air handlers and Munters as a company," said John Sasser VP Operations for Sabey Data Center Properties.