How to keep a server cabinet cool
The temperature inside a cabinet is affected by many variables, including door perforations, cabinet size, and the types of components housed within the cabinet. The most direct way to cool network equipment is to ensure adequate airflow. The goal is
that every server, every router, every switch has the necessary amount of air no matter how high or low it is in the cabinet. It takes a certain volume of air to cool a device to within its ideal temperature range. Equipment manufacturers provide
very little guidance about how to do this; however, there are some very basic methods you can use to maximize the ventilation within your cabinets.
1 - Ensure airflow through cabinet door
Most major server manufacturers recommend that the front and back cabinet doors have at least 63% open area for airflow. You can achieve this by either removing cabinet doors altogether or by buying cabinets that have perforated doors. Because most servers,
as well as other network devices, are equipped with internal fans, open or perforated doors may be the only ventilation you need as long as your data center has enough air-conditioning to dissipate the heat load. You may also want to choose cabinets with side panels to keep the air within each cabinet from mixing with hot air from an adjacent cabinet.
2 - Determine type of convection cooling needed
a) Natural convection cooling
The flow of heat from a warmer environment to a cooler environment occurs naturally when the ambient temperature surrounding an IT cabinet is cooler than the internal temperature. The heat from the enclosure will naturally radiate through its walls, and
the internal temperature will be lowered accordingly. Although this method is by far the simplest, it is also the least effective because the temperature difference between most enclosures and their ambient environments is not big enough to sufficiently cool the components inside the enclosure.
b) Forced convection cooling
The amount of heat that transfers from a warmer area to a cooler area can be increased with the addition of a fan or blower to decrease the thermal resistance of the barrier between the two areas. In the case of an IT enclosure, fans can provide affordable
forced convection cooling to reduce the internal temperature. But what happens when the outside air has contaminants like dust and dirt or oil? The fan may provide the cooling you need, but it will deposit these contaminants on electrical components at the same time. When air contamination might be a problem, the best solution is a closed-loop air-to-air heat exchanger. However, just as with natural convection cooling, the amount of heat that can be transferred away from the components inside the enclosure is limited by the ambient air temperature.
c) Active convection cooling
When natural convection or forced convection does not provide enough heat transfer to adequately cool the components inside the enclosure, an air conditioner may be required. An air conditioner provides the closed-loop system that is needed when the components
inside the enclosure must be protected from environmental factors such as dirt, dust, or liquids. Furthermore, air-conditioned cabinets - like Black Box's ClimateCab™ Climate-Controlled Cabinets - even let you save energy because you only need
to cool the cabinet and not the entire room or IT center.
Calculating the required cooling capacity is an essential step in selecting a properly sized air conditioner. Cooling capacities for enclosure air conditioners range from 1.000 BTU/hour to 20.000 BTU/hour, which is based on the internal
heat load and the heat load transfer. An accurate calculation is therefore a critical step in selecting the right AC unit for your application.
Get to know more about Black Box's ClimateCab™ Cooling Capacity..
3 - Placement of equipment and server fan
Don't overload the cabinet by trying to fit in too many servers —75% to 80% of capacity is about right. Leave at least 1U of space between rows of servers for front-to-back ventilation. Maintain at least a 4 cm clearance between equipment and the
front and back of the cabinet. And finally, ensure all unused cabinet space is closed off with blank panels to prevent mixing of hot and cold air.
You can increase ventilation even more by installing fans to actively circulate air through cabinets. The most common cabinet fans are top-mounted fan panels that pull air from the bottom of the cabinet or through the doors. For spot cooling, use a fan
or fan panel that mounts inside the cabinet.
4 - Monitor temperature
To ensure that your components are operating within their approved temperature range, it's important to monitor conditions within your cabinets. The most direct method to monitor cabinet temperature is to put a thermometer into your cabinet and check
it regularly. This simple and inexpensive method can work well for small installations, but it can't raise the alarm if the temperature goes out of range, and must be checked manually. Another simple and inexpensive addition to a cabinet is a thermostat
that automatically turns on a fan when the cabinet's temperature exceeds a predetermined limit.
Many network devices come with SNMP or IP-addressable internal temperature sensors to tell you what the internal temperature of the component is. This is the preferred temperature monitoring method because these sensors are inside your components where
the temperature really counts. Plus you can monitor them from your desktop—they'll send you an alert if there's a problem. There are also cabinet temperature sensors that can alert you over your network. Although these sensors only monitor cabinet temperature, not the temperature inside individual devices, these sensors can be a valuable addition to your cooling plan, especially for older devices that don't have internal sensors. View Black Box's AlertWerks Environmental Monitoring System for more information on cabinet-monitoring sensors.
Server Cabinet Cooling Solutions
Keeping your data and server cabinets cool doesn't have to be complicated. Just remember not to overcrowd the cabinets, be sure to provide adequate ventilation, and always monitor conditions within your cabinets. Black Box's Server Cabinet Cooling solutions
ensure you protect your essential IT equipment with the highest-quality cooling solutions available, such as: