Keeping cool in data halls
13 June 2019
A Condair ME evaporative humidifier is providing adiabatic cooling in an indirect cooling system from EDPAC at the Cork Internet Exchange (CIX) in Ireland.
EDPAC’s indirect air-to-air evaporative cooling system will be maintaining the temperature across CIX’s data halls without using any chillers and with 75% less energy than a traditionally cooled data centre.
The installation of the new low energy cooling system was part of a €6M extension at the family–owned 2,800m2 data centre, partly funded by the Excellence in Energy Efficient Design (EXEED) programme.
The EDPAC air handling system cools without chillers by creating two airstreams; one internal and one external. The internal airstream circulates air to and from the data halls and the external airstream draws in, then vents, ambient outside air. Both airstreams pass through a series of heat exchangers to transfer cool thermal energy from the external to the internal airstream, without either physically mixing.
In order to boost the cooling capacity of the system, and keep the data halls at 24°C all year round, evaporative cooling is used to reduce the temperature of the external airstream below that of the ambient outdoor air. A series of Condair ME evaporative humidifiers are located in the walls around a penthouse ventilation area, created across the top storey of the building. As air is drawn into the building through louvres, it passes through these Condair MEs, before entering the penthouse ventilation area where the EDPAC AHUs are located.
The Condair ME consists of an evaporative matrix section, which sits across a duct, and a hydraulic module that continually pumps water up to the top of the matrix to keep it moist. As air travels through the Condair ME’s wet matrix, it absorbs water and is cooled by several degrees.
Noel Lynch, managing director at EDPAC, comments: “By reducing the temperature of the outside air entering the penthouse ventilation area with the Condair MEs, the air being drawn into the external airstream of the air handling units is significantly cooler than the outside air. This enables the indirect cooling system to maintain the desired data hall temperature of 24°C, even in the hottest months of the year.”
Lynch continues: “The complementary technologies of air-to-air heat exchange and humidifier-based evaporative cooling is a considerable improvement to existing indirect data centre cooling systems. The strategy offers very low energy climate control while being easy to manage, as it doesn’t have a wet spray section with the onerous administrative obligations that this can place on a building operator.”
Four AHU modules, each delivering up to 400kW of cooling, have been installed above the data halls at CIX, alongside four Condair ME evaporative humidifiers. While the outside Cork weather remains below 21°C, air-to-air cooling alone is sufficient to maintain the required data hall condition. When the outdoor temperature rises above this, the Condair MEs operate to provide up to 300kW of cooling to each AHU.
Donal Deering, energy consultant at Smart Power, a Dublin-based energy consultancy that worked on the project, comments: “The expected electrical demand across the year is just 12kW per 400kW AHU module, including the electrical consumption of the Condair ME evaporative humidifiers. Typical PUE values across Irish data centres is 1.5-1.7 but the use of adiabatic cooling at CIX will lower the facility’s overall PUE to less than 1.4. The energy savings are expected to be 75% of that which would otherwise be used in a traditionally cooled data centre.”
Deering concludes: “The CIX evaporative cooling project is an exciting, innovative project and credit must go to Jerry Sweeney, chief executive at CIX, and Noel Lynch at EDPAC for their pioneering efforts.”