Why it is important to maintain temperature conditions in a server room. How a server room cooling usually works

  • Published In: Tutorial
  • Created Date: 2014-09-21
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To begin with, let us examine what is a regular server room. As a rule, it is a room indoors, often not of a big size, which is sufficient to place server racks with a specific set of network equipment. The most often a server room is in a basement or in an attic. Therefore, a location of a server room is not the first priority to think about for an administration of an organisation.

To begin with, let us examine what is a regular server room. As a rule, it is a room indoors, often not of a big size, which is sufficient to place server racks with a specific set of network equipment. The most often a server room is in a basement or in an attic. Therefore, a location of a server room is not the first priority to think about for an administration of an organisation. 
Let us suppose that a server room is located in a basement. In this case air conditioning of a room will be sufficiently done by a common air conditioner (a split system) that is available on the market. However, there is a need to take into account that soil is nearby and a room is located below a soil level. Probably, you will have to deal with an excessive humidity. In addition, you may face with a presence of heating and water supply communications in a server room or very close to it, which will directly influence temperature conditions. Let us suppose that a place for a server room was chosen at the last turn and a room appeared to have a heating radiator or hot water communications. No doubt this circumstance will additionally load a cooling system and will add certain risks for equipment to fail in case of a cooling system failure. But you should not forget about certain cases when there is a need to install an additional heating system to maintain temperature conditions. You will need a manageable heater to do this. A cooling system as well as a heating system must be managed by a standardized device, which would allow to read data from temperature and humidity sensors and send control commands to heating or cooling systems according to previously set threshold values. Below you can find several requirements for climate conditions in a server room:

  1. A possibility to turn off a heating system must be supported;
  2. An air conditioning system must be autonomous;
  3. A temperature in a server room must be in range from +18 to +24 degrees of Celsius (64-75 degrees of Fahrenheit);
  4. Air humidity in a server room must be in a range from 30% to 50%.

Let us examine a situation when a server room is located in an attic. Besides warmth that is produced in a process of equipment operation, very close location of a server room to a roof, which is warmed up by the sunlight, will facilitate rising of a temperature. Again, a risk of equipment overheating, causing its failure, is high enough.

So, how does a cooling system work in a server room? As a rule, an air conditioner (a split-system) is used, which works all year round in a non-stop mode, i.e. 24 hours a day and 7 days a week. A cooling system must be reliable enough to operate uninterruptedly for a long time and maintain necessary temperature and humidity levels. Besides, during a winter season when the temperatures are below zero, equipment in a server room may need some heating. There is a need to have a management system to turn on/turn off a heating system, which can control a heater on the basis of data from temperature and humidity sensors.

Humidity value is also important for computer equipment operation. When a humidity value is high, condensate can appear inside devices and cause corrosion, which is highly not recommended for the equipment. There is a need to choose an appropriate air conditioner or use a dehumidifier to maintain ideal air humidity. Certain modern split-systems allow to reduce temperature, provide a constant purified air flow but do not allow to maintain ideal air humidity. Such split-systems in server rooms should be avoided. As a rule, only one air conditioning unit is mounted in a room, which is not sufficient for providing normal temperature conditions: in case if an air conditioner suddenly fails, the equipment can get overheated, which can cause its failure. Therefore it is recommended to mount at least two air conditioners. A capacity of each separate air conditioner should be sufficient for creating necessary climate conditions in a server room. Also it is possible to adjust sequential work of air conditioners to increase their wear out time and ensure their faultless operation by using modern climate monitoring systems in a server room. When using sequential operation features, it is possible to do a preventive maintenance to air conditioners, which will finally result in increasing their life time and securing the equipment from unwanted temperature rising as well as equipment failure.

An Example of Reserving Air Conditioners:

Стопроцентное резервирование, установлены два кондиционера

An internal heat removal system of modern devices is developed in a way to provide cooling of all internal components that produce heat while working. However, a body of a server is not sealed and there is a heat exchange with an environment of a server room, hence it is a mistake to think that a temperature of an air inside a body will be significantly less than a temperature in a server room. There is a need to take into account the fact that a temperature of an air in a server room outside of a communication closet, inside a communication closet and directly inside a body of server can be different. Therefore it is recommended to install temperature sensors not only on a ceiling of a server room, but also into each communication closet for having a hard information about climate conditions both in closets and outside. With the aim to provide a proper air circulation in a server room there is a need to design mounting of an air conditioner or a heating system regarding air flows that are created by these systems. To accomplish this, there is active ventilation in server closets that ensures a cooled air access directly to a server closet. Appropriate installation of devices in a server closet is an important factor as well. It should be fulfilled taking into account dimensions of devices and their heat production. Proper decision is to use 1U ventilators among equipment that produces a lot of heat, to provide ventilation and remove unnecessary heat.

An Example of 1U Ventilators:

Server Rack Fans and Rack Mount Fan Assemblies 

Ventilators, Installed into a Lower Part of a Closet for an Air Flow:

Ventilators, Fulfilling Hot Air Removal to Outside of a Closet:

On the picture below you can see improper mounting of an air conditioner. Let us consider some obvious mistakes:

  1. An air conditioner is mounted right above a communication closet. If there is a leak in a conditioner, the equipment in a communication closet will be flooded with liquid that can lead to unwanted consequences as tough as a short circuit and physical burning out of equipment components.
  2. An air conditioner is mounted almost right up to a ceiling. Such mounting makes possible technical maintenance operations more difficult and complicates an air flow.

So, why is it really necessary and important to maintain certain temperature conditions in a server room? 

As a rule, a server room has highly important and very expensive equipment. Its failure or downtime can cause material and financial loss. Let us take a look inside a modern server and try to find out which components are the most critical to temperature fluctuations.

Hard Disk.

Perhaps it is the most important component of a system. Accordingly, a hard disk failure can be a critical issue for an organisation. Hard disk components are sensitive to temperature fluctuations: to sharp rising and falling of a temperature as well as to overheating. Rising of a temperature usually causes expansion of a material, from which heads are made, as well as expansion of a head positioning system and magnetic disks. Overheating can cause a hard disk failure, which will consequently lead to unwanted loss of important and valuable information.

Random Access Memory.

A modern random access memory is equipped with a passive cooling system and does not need any additional cooling. However, there is a need to remember that a passive cooling system is effective only in a certain range of temperatures. If a temperature in a server room is rising, none radiator on a line memory will help to save a random access memory from overheating.

Processor.

Modern processors have protection systems from overheating. Their sensors will alarm an operation system about overheating and will prevent processor operation at high temperatures.

Motherboard Chipsets.

So called computer north bridges and south bridges are powerful heat producers. Indicated controllers are usually equipped with passive cooling radiators. At the same time, they are sensitive to air temperature fluctuations in a server room.

To sum up all the information about server components discussed above, I would confidently say that a built-in server cooling system is efficient enough in a certain range of temperatures. However, when a temperature exceeds limits of an operation range, a cooling system may not be able to cope with a heat removal issue. In addition, there is a need to avoid sharp temperature fluctuations, which can cause loss of motherboard elements features of a server.

A server room may have plenty of expensive equipment that is critical to rising of a temperature and its sharp fluctuations, and due to this fact it is necessary to choose a cooling system properly into a server room. It is necessary to take care about a backup air conditioner and a controlling management system of conditioners in case if a main conditioner fails. Also there is a need to remember that the majority of modern devices produce enough heat and can increase a temperature inside shortly. Moreover, it is necessary to properly choose a split-system, which satisfies the requirements of a server room. 

Conclusion.

i would like to remind that modern computer equipment is developed taking into account its operation in certain climate conditions. Therefore, working with the equipment in conditions that are different from the ones recommended by a manufacturer, may cause equipment to fail, with no warranty repairs. Considering all mentioned above, we recommend using reliable climate control systems as well as reliable systems of climate maintaining in a server room.

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