Evaporative cooling solutions are relatively new to data center cooling, but they have been used in residential settings for years in place of traditional air conditioning with refrigerants. They’re best suited for low-humidity environments with a high temperature and a consistent water supply – in other words, a hot data center where humidity is already carefully monitored to avoid damaging sensitive electronics.
A new evaporative cooling system uses innovative materials to improve performance.
What is Evaporative Cooling?
In a nutshell, evaporative cooling is an alternative to air conditioners that use refrigerant, which can contribute to ozone depletion and also require more energy to operate.
Evaporative cooling relies on the natural evaporation of water to cool a space by drawing air across wet filters or pads. The water absorbs the heat efficiently, and the cool air that’s left is redistributed into the space.
It has been slow to catch on in data centers despite its low cost (as little as 25 percent of traditional HVAC in some cases) because it introduces more humidity into the space where it’s installed. However, because humidity is so dangerous for computing equipment, many data centers already have the appropriate humidity controls included.
How Does the New Data Center Evaporative Cooling Model Work?
Damena Agonafer, assistant professor of mechanical engineering and materials science at Washington University in St. Louis, has developed a unique evaporative cooling system. His design is the first evaporative cooling solution to use a porous membrane with microscopic pillars. The membrane retains refrigerant – a key component of the system, since water can’t be used safely in electrical applications – and ultimately removes heat faster than a traditional evaporative cooling system.
Dielectric refrigerant has a low surface tension, unlike water, so it can “wet” any standard surface in the same way that water wets filters or pads in other evaporative cooling solutions.
“This work is the first demonstration of low surface-tension liquid within porous membrane structures,” Agonafer says. “There are many ways to retain liquid inside or behind the porous membrane structure with high surface-tension liquid, such as water, with surface chemistry, but you can’t do any type of surface treatment with low surface-tension liquid, so this requires a certain type of microstructure to form an energy barrier and ‘pin’ these liquids.”
Commercializing this technology could lead to new developments in data centers and other energy-intensive applications like health care, Agonafer notes.
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