Ambient Air Cooling and Other External Environment Factors

Posted by Instor on Jun 27, 2017 6:22:00 AM

As you might imagine, there can be a significant difference in cooling costs by lcoating your data center in a warm climate as opposed to a cooler one. But cooler climates bring added concerns, such as electrostatic discharge. Learn how to make your data center's location work to your advantage today. 


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Data Centers in Alaska vs. Arizona: The Difference is As Big As You Might Imagine

Many of us have experienced the cold, dry weather of during winter in the northern climates where we quickly return home seeking to warm up. It’s during these times that we may also experience electrostatic discharge (ESD) voltage from walking across a floor with carpeting and touch a metal object such as a door knob. However, unlike our homes, many commercial buildings use outside ambient air through opened dampers or economizers and as supply air into the air handlers even during the winter to take advantage of “free cooling.” Locating a data center in the north such as Fairbanks, Alaska is very different than locating it in Phoenix, Arizona, for example. When comparing the annual diurnal temperatures for each location, we find that this results in 27.55° Fahrenheit (F) and 75.05° F, respectively. Use of free cooling can aid in the cooling management plan which would translate into energy savings - data center cooling is inherently tied to energy consumption for the HVAC and CRAC systems.

Many data centers managers may be reluctant to consider free cooling during winter months because of the naturally dry air that can be problematic in the form of ESD. The combination of ESD and electronic circuits (i.e., server racks, switches, routers, etc.) could become inoperable unless relative humidity (RH) is introduced back into the building to counter these affects. When compared to the overall power consumption, lowering cooling costs would be more advantageous.

A Research and Markets’ 2017 report, “Data Center Cooling Market by Solution (Air Conditioning, Chilling Unit, Cooling Tower, Economizer System, Liquid Cooling System, Control System, and Others), Service, Type of Cooling, Data Center Type, Industry, and Region - Global Forecast to 2021” estimates that the cooling market will grow to 14.95 percent  Compound Annual Growth Rate (CAGR) or $14.28 Billion by 2021. A few of the major market drivers include liquid cooling, increased data center efficiencies with lowered costs, reduced energy consumption; and the dense, modularity of newer technologies.

Although data center power consumption has somewhat leveled off over the years, the upward trend has been widely reported concerning how many billions of kilowatt-hours per year is used. The industry focus continues to be on reducing energy use and in 2016; ASHRAE (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) created the Standard 90.4-2016, “Energy Standard for Data Centers.” With an eye toward the goal of energy and cost reduction, newer technologies are being developed which include low-speed ventilation (LSV), new refrigerants, liquid cooling and many more. The ASHRAE Technical Committee (TC) 9.9 has published a white paper concerning data center temperature and humidity guidelines, 2016 ASHRAE Data Center Power Equipment Thermal Guidelines and Best Practices, which identifies set points to be used given an acceptable range of temperature and RH. The ASHRAE Class A1 to A4 Recommended Temperature and RH Range is 64.6°F to 80.6°F (18°C to 27°C) and 40% to 60% RH (5.5°C to 15.0°C dew point). Another way to help in understanding how these parameters are interrelated is to use the psychometric chart – it includes ambient indoor air temperature or dry bulb, dew point, RH and pressure.

What to do with the excess heat being generated - one complimentary solution to using free cooling is to consider thermoelectric technology similarly to how NASA uses it to turn heat into electricity to power spacecraft. Some data centers use thermoelectric generators (TEG) to convert excess heat into electricity.

Understanding how to provide cooling management for the data center is now trivial task. There are a couple of free, online tools available to assist in cooling management - The Green Grid: Free-Cooling Estimated Savings and the U.S. Department of Energy (DOE) – Lawrence Berkeley National Laboratory (LBNL) - Data Center Air Management Tool (v.1.18) which estimates energy reduction, kWh reduction percentages, and associated cost savings for fans and chillers.

For your next design or build-out, contact your partners at Instor Solutions for a consult to help create a scalable infrastructure for your data center.


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Topics: Cooling