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How to Monitor the Air Conditioning in Your Computer Room

Computer Room Air Conditioning (CRAC) are cooling units for computer rooms. As the equipment in your computer room becomes more complex and compact, computer rooms are watching their power draw and heat generation quickly rise. The increase in computer room power consumption, density, and heat generation requires a more exact approach to a computer or IT room air conditioning design than ever before.

Computer equipment room or data center cooling used to be a relatively painless affair. When data centers were using less power and generating less heat per square foot, a technician or administrator could simply offset the heat from equipment with additional CRAC units. Simply pumping cold air in the room was enough of a cooling solution to bring down the temperature.

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Now, however, that proves to be a feeble way to cool your computer room. Hot air is generated by computer room equipment quickly. Simply turning the thermostat down doesn't offer the cooling you need to safeguard your equipment. Cool air distribution must occur to ensure that heat is displaced.

Keeping the Modern Computer Room Cool

To achieve an effective computer air conditioning system, many technicians are placing racks in hot and cold configurations.

They place their computers and racks on raised floors, two tiles apart, with their air intakes facing each other. The CRAC cooling system pumps cool air through perforated floor tiles between the racks, the computers and racks intake the cool air and exhaust hot air into the opposing hot aisle. Computer room air conditioning units on the floor then pull in the hot air exhausted into the hot aisles, and release it underneath the floor tiles, completing the cycle.

In this way, a CRAC unit air handler can keep cool air running through the system and help keep a steady airflow through the environment.

It's even become common to take advantage of the space above computers and racks and make another "hot aisle" of the room's ceiling, where heat normally escapes and hovers. To keep the whole computer room cool, technicians advocate turning the area above racks into a hot air plenum by placing ducts and more CRAC units. Hot air escapes into the plenum to be pushed back into the system, below the floor, where it can be cooled and released back into the system.

This works for your computer room by removing hot air from the data center. Bringing in more hot return-air helps the heat exchangers in the CRAC units produce colder air to pump out to the computer room floor.

Hot cold aisle strategy
A diagram of the hot-cold aisle strategy for computer room air conditioning

Monitoring Devices for Your Modern Computer Room

Of course, monitoring the quality of the air conditioning in the computer room means much more than simply monitoring the CRAC unit components themselves. Even if they're working, there's no guarantee that the cool air they pump into the environment is making it to your equipment. And since there's no guarantee of homogenized equipment across the computer room, it's likely that you'll have hot and cold spots.

There are two main things you'll have to check to ensure that your CRAC units are working properly and keeping your computer room cool. First, you'll have to check the airflow both above and below the floor. Then, you'll have to check the air temperature throughout the room to find which areas are hot and which areas are cold. Fortunately, there are a number of small devices that can fit in line with your computers and monitor your computer room's environment.

The TempDefender RTU

DPS Telecom's TempDefender is specially designed to monitor conditions in your computer room. This small, rack-mountable RTU connects to up to 16 analog sensors. These sensors measure the temperature, humidity, airflow, smoke, or any other conditions you may be worried about in your server room.

Sensors for the TempDefender are daisy-chainable via RJ-11 connectors and can be assembled in any configuration. This allows you to run a set of sensors through your server room without running 16 cables in parallel from your room, all the way back to your TempDefender. You can run sensors from a temp defender to monitor airflow in your hot aisles and hot and cold spots, and humidity at the return air space, all from one RTU.

TempDefender monitors your computer room cooling system to ensure the safety of your equipment and optimal operating conditions. Preventing hardware failures and shutdowns due to poor data center conditions keep costs down.

The TempDefender also has 8 dry contact alarms and 3 control relays. This way you can augment monitoring and remote control for devices inside your cabinet. Or, mount your temp defender near your CRAC unit HVAC equipment and monitor both environment and HVAC equipment for failures.

A computer room is a delicate environment, and you don't want to babysit a bunch of computers and air conditioners. When TempDefender measures a threshold alarm for any of the environmental factors it's monitoring, it can send a trap to your master station or email you directly. It also has an intuitive web interface, so you can see what's going on in your data center in real-time.

NetGuardian 216: Making Sure CRAC Units Perform at the Equipment Level

Of course, you don't have to monitor your whole data center with one device or even run sensors throughout the data center. Hot, cold, and humid spots will appear throughout the room naturally. That's because varying equipment will emit varying amounts of hot air, and because air is simply a hard element to control. You could simply install monitoring devices individually with your cabinets, so you can monitor every individual cabinet, thereby giving you a good overall view of the computer room environment.

DPS Telecom recommends the NetGuardian 216 device for this sort of application because it has both dry contacts and analog inputs. The dry contacts are used to monitor the data center equipment in your cabinets, and four analog inputs are used to measure the environment inside or just outside your cabinet.

Computer room cooling requires a strategic plan and a large amount of environmental data. However, getting the data you need to maximize cooling in your computer room doesn't have to be hard. The TempDefender and the NetGuardian series remotes are perfectly equipped to handle analog and discrete coverage within the computer room, giving you the information you need to keep your computer room cool.

To know more about our remote monitoring environmental solutions, just reach out to us.

Protect your Computer Room: Part 2