Many server rooms start out cooled by an ordinary split-type or window aircon. It works at first. Then the room fills with more equipment, the aircon runs non-stop, and one hot afternoon it trips or freezes up, taking the servers with it.

Built for different jobs

Comfort aircon is designed to keep people comfortable for part of the day. Electronic equipment produces heat continuously, day and night, and needs stable conditions rather than occasional cooling.

• Operation: comfort units are designed for intermittent use, while precision units are built to run 24/7, all year
• Control: precision units hold temperature and humidity within tighter limits
• Humidity: precision units actively control humidity, while comfort units mostly remove moisture as a side effect
• Airflow: precision units move more air to carry heat away from equipment racks
• Monitoring: precision units usually include alarms and remote monitoring

Why temperature and humidity matter

Equipment manufacturers and industry guidelines, such as those published by ASHRAE, recommend keeping server inlet air at roughly 18 to 27 °C. Too much humidity risks condensation and corrosion, while too little increases the risk of static discharge. UPS batteries are also sensitive to heat, and their life shortens quickly in a warm room.

When comfort aircon may still be enough

For a small comms closet with a few devices, a properly sized comfort unit can be acceptable, especially with a second unit for backup, a temperature alarm and regular maintenance. As the heat load grows, or once the equipment becomes critical to the business, a PACU becomes the safer choice.

Signs your room has outgrown its cooling

• The aircon runs constantly and the room is still warm
• Some racks are noticeably hotter than others
• Equipment alarms or unexpected shutdowns on hot days
• Water dripping or ice forming on the unit
• No backup cooling if the single aircon fails

Make the cooling you have work better

Good airflow management helps any cooling system: blanking panels in empty rack spaces, sealed cable openings, and hot or cold aisle containment. For existing HVAC units, CONTINEWM nets can also reduce energy use. The manufacturer reports around 25 percent lower HVAC energy use at reference sites, although actual results depend on the site and equipment.

How ARCED can help

ARCED installs and maintains PACU and aircon systems, reviews cooling capacity for growing rooms, and supplies containment and energy-saving solutions. See our PACU & Aircon Services and cooling products.