Unit configurations. Emerson 3000, Liebert Challenger 3000

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For sensitive electronics, environmental control is more than simple cooling. “Comfort” air conditioning systems are designed for the comfort of people and simply cannot provide the kind of environment required by high performance computer or communication equipment.

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The high density heat load in a computer room or other similar application is beyond the capacity of ordinary air conditioning systems.

Sensitive electronics are best maintained in a stable environment of 72°F ±2°F (22.2°C ±1°C). Because computers and communications equipment generate large quantities of heat in small areas, six to 10 times the heat density of normal office space, the air conditioning system must have more than just enough cooling capacity. It must have the precision to react quickly to a drastic change in heat load and prevent wide temperature fluctuations—something a large building system cannot do.

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A clean environment of properly filtered air is essential. Build-up of dust and fibers attracted by operating electronics can cause faults and impair the operation of electromechanical devices, such as switches and disk drives.

In short, today’s electronics need the same precision environmental control that mainframe computers need. The difference is that instead of one large computer room there are several small, often crowded rooms, widely dispersed throughout a building, plant or campus. Conditions and requirements can vary widely.

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Comfort conditioning systems cannot be relied upon

24 hours per day 365 days per year. They are typically designed to operate 10 hours per day, from spring to autumn. Many “comfort” systems have no provision for winter operation. A precision environmental control system is designed for operation at temperatures down to -30°F (-34.4°C).

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The electronic equipment must be protected from both internal condensation and static electricity discharges.

Maintaining the correct humidity level in the room is just as important as maintaining proper temperature. When humidity is too high, condensation may form inside electronic equipment and damage it. If humidity is too low, static electricity could disrupt operation or even shut down the electronic system.

An ordinary building system cannot normally control the environment within these boundaries.

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Standard 60 Hz units are UL listed and CSA

(NRTL-C) certified. NRTL-C meets both U.S. and Canadian government safety requirements, providing fast, hassle-free inspection and building code approvals. The units are also MEA listed for New York City applications.

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Computers and other sensitive electronics require greater air volumes than ordinary air conditioning can provide. Typical comfort systems are designed to provide between 300 and 400 CFM (cubic feet per minute), (500–700 CMH) per ton of cooling. Computer systems require between 500 and 600 CFM

(850–1020 CMH) per ton. The high density heat load in a relatively small space requires more changes of air than a less dense “comfort” application.

While a normal office space requires only two air changes per hour, a room filled with electronic equipment requires up to 30 changes per hour. Without proper air volume, hot spots and temperature fluctuations could develop within the room. Also, greater air volumes provide the higher sensible heat ratios required by electronic computer equipment.

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