When data center managers think of environmental management and monitoring they typically think of temperature sensors, and perhaps humidity sensors but, where should they be placed? Though temperature sensors remain the most prevalent sensors, there are many sensors which can be usefully deployed in a data center. There are sensors for determining whether a cabinet door is open, the difference in pressure between two locations, the rate of airflow, and the presence of water. There are even sensors for tracking IT assets.
Sensors are an easy to install, cost-effective way to reduce energy costs, improve reliability, and increase capacity for future data center growth. But most managers do little beyond monitoring the temperature by checking the thermostat reading on the wall. By using environmental sensors you can optimize your data center ecosystem to ensure that you are meeting equipment guidelines, reducing operational costs, deferring capital investments, and improving your power usage effectiveness (PUE). Following are some of the sensors that will be useful in a data center:
One of the many benefits of sensors is an end user being able to set thresholds and alerts. For example, a temperature sensor can be set to send an alert if the temperature rises to a level where it might damage sensitive IT equipment. It can also be set to send an alert if the temperature falls below a threshold to ensure that energy isn’t being wasted by overcooling the data center. It may even be necessary to set different thresholds for different locations. For humidity, accuracy is less critical though data center managers should ensure that relative humidity (RH) guidelines are followed.
Properly placing temperature sensors on a rack means temperatures can be plotted to ensure that IT devices don’t overheat and that energy isn’t being wasted by overcooling. Plotting individual sensors allows data center managers to identify hot spots requiring additional cooling or changes in the airflow or air pressure of the system to ensure adequate cooling is reaching all the locations where it is needed.
The area under a computer room’s raised floor is quite often used as a plenum for chilled air. However, this space can become cluttered with networking and power cables, which can restrict the flow of cooling air. Often, when new power or network cables are run under the floor the old cables are left in place. Over time these obstructions build up and can seriously restrict air flow. Perforated tiles allow the chilled air from the raised floor plenum to flow up to cool IT devices. Not only can this airflow be blocked by obstructions within the plenum but perforated tiles are available with various size holes. A cooling problem might be solved by changing to a tile with larger or smaller holes. It is important to monitor the chilled airflow, but it can also be important to monitor the hot air return airflow.
Contact closure sensors can be set to be normally open or normally closed. They are often connected to third-party sensors and send an alert when the third-party sensor is triggered. For example, a contact closure sensor could be connected to a third-party smoke detection sensor and send an alert when smoke is detected. Or a contact closure sensor could trigger a webcam to take a picture when a cabinet door is opened.
Water sensors can be used under racks to detect leaks. There are individual sensors and “rope” or “cable” sensors. A rope sensor can be laid under a row of racks and detect water anywhere along its length. A rope sensor can also be wrapped around pipes to detect leaks.
A webcam itself can be considered a sensor in that it monitors a data center by providing images. These can be still images as was mentioned in the example above in the contact closure section or video can be streamed such as in a surveillance application.
A data center, whether a room or an entire building, is all about what is happening at the rack. The right environment monitoring and metering at the rack can lead to some nifty data center improvements – right sizing the data center and just-in-time expansions to save on capital expenses; improved energy efficiency, IT productivity and utility; and better integration with cloud computing.The ability to monitor environmental conditions will go a long way in helping the data center manager manage energy costs.
Source: Raritan International