A breakdown of the air conditioner in the office does not entail the termination of the work of the staff, does it? The situation is quite different with server rooms, where uninterrupted air cooling is required. By including the air conditioning rotation unit in the system, even short-term exceeding of the temperature limit values is excluded.
This solution prevents the failure of server equipment and creates conditions for the stable performance of service tasks. We will tell you how to organize a rotation block. We will explain how to reserve air conditioners, we will show you how to install and configure the device.
The content of the article:
- Air temperature indicators in the server room
- Purpose and structure of the rotation unit
- Redundancy schemes for air conditioners
- Features of installation on the example of BURR-1
- Rotation unit working principle
- How the setup is done
- Equipment care rules
- Selection factors and additional functionality
- Conclusions and useful video on the topic
Air temperature indicators in the server room
Rotation units have been introduced into the air conditioning systems of many laboratories, data centers, production workshops in high-tech industries. This is an integral element of server room equipment, which are available in almost every serious organization.
In the age of information technology, even new, developing companies strive to use their own server hardware for processing, storing and exchanging data with partners and customers.
There are strict requirements to the temperature regime in the server room, the fulfillment of which is possible only with two or more air conditioners.
A separate technological room is allocated for server equipment, the so-called server room, where it is necessary to maintain the operating conditions specified in the technical documentation by the manufacturer. In particular, one of the most important parameters is the air temperature.
The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) recommends that server room temperatures be between 18 ° C and 27 ° C. Most specialized companies, for example, those providing hosting services, do not allow the air temperature to rise above 24 ° C.
An increase in temperature, even for a short time, can cause a malfunction in the operation of server equipment, and to eliminate the accident, it will be necessary to replace expensive components
Such strict temperature limits are due to the operational characteristics of the server computers. Local overheating of certain devices that make up the server leads to their breakdown. As a result, it all comes down to the loss of important information, disruptions in production, commercial, logistics processes and, as a result, to the loss of reputation and profits.
The modern server is equipped with an internal heat dissipation system. All internal components that generate heat during their operation are cooled. But it is impossible to completely avoid heat transfer due to the leakage of the housing. Despite the radiators and even liquid cooling, the temperature inside the case will be close to the ambient temperature.
The following components are most sensitive to climatic conditions of operation:
- CPU;
- HDD;
- RAM.
As the temperature rises, the materials that make up the hard drive components expand. This leads to the failure of magnetic disks, heads, positioning systems. Hard drive problems can lead to the loss of important information.
For local cooling of server processors and RAM, metal heatsinks are used, but with a significant increase in the ambient temperature, they are not able to provide protection against overheating
In modern servers, random access memory devices are installed, equipped with their own passive cooling system (radiators). But this does not change the state of affairs. Radiators can save RAM only with a very short and slight increase in temperature. But with a stronger heating of the air, they are ineffective.
The processor protection system automatically responds to overheating, which leads to a server shutdown and the impossibility of its normal, uninterrupted operation. Many microchips, in particular, on the south and north bridges, do not tolerate high temperatures.
Do not expect that if the outside (street) temperature is within an acceptable range, you can refuse to cool the air in the server room. It is necessary to take into account all indicators of heat release and heat gain. Thus, the thermal power of servers is 80-90% of the consumed electrical power and often exceeds 1 kW.
So, the use of expensive and important for solving business problems equipment that is sensitive to temperature rise and fluctuation, requires properly organized air conditioning, in which each one split system should run smoothly.
Purpose and structure of the rotation unit
The organization of the cooling system by installing not only the main, but also spare, backup, air conditioners in itself does not save the situation.
It is necessary to coordinate the operation of all devices in such a way that the temperature in the room remains stable under any conditions. For this purpose, specialized complexes are used, which are often called simply coordinators.
Organization of an air conditioning system, including main and backup air conditioners, one manager unit, two execution units and three temperature sensors with a bus connection for fire warning and emergency situations
The standard complex includes a control unit and executive units. Together they perform the following basic functions:
- control over the operation of the system;
- switching air conditioners in case of breakdowns;
- ensuring alternate functioning;
- even distribution of working hours.
A reliable air conditioning system in the server room consists of at least two air conditioners: the main one and the backup one. Each of them, according to its technical characteristics, must be able to maintain the required temperature conditions in the server room.
In the event of a breakdown of one air conditioner, the rotation unit quickly turns on the second, serviceable, device. When performing this function, thermal sensors are used that measure the temperature and respond to its slightest increase. The redundancy function helps not only in emergency situations, but also, for example, in the planned maintenance and repair of air conditioners.
One of the options for organizing a cooling system in a server room with a redundancy unit and power supply of air conditioners from a separate machine
The implementation of such a solution allows you to change filters, charge air conditioners with refrigerant, perform more complex operations at any convenient moment, while continuing to maintain an optimal microclimate in the server room the room.
The rotation block also provides alternating operation air conditioners and split systems and as a result, the cumulative time of their work is approximately the same. As a result, the overhaul period and the operational life of the cooling equipment are extended.
Redundancy schemes for air conditioners
It is possible to implement various redundancy schemes, which are conventionally designated as N + 1 and 2N, where N - the number of air conditioners performing a similar function in the system (from the English "Need" - "Need").
The simplest scheme, involving the use of only one backup air conditioner, is N + 1. If the rotation system is not configured, the standby air conditioner is activated only in emergency cases and takes over the entire load.
The system can have several main working air conditioners, and each of them has a backup air conditioner, which is designated as 2N and means 100% redundancy. It is clear that the more redundant air conditioners, the higher the fault tolerance of the system.
Features of installation on the example of BURR-1
We will show how the installation is performed with a specific example. In Russia, BURR-1 rotation and redundancy control units are widespread, working in conjunction with specialized executive BIS-1 units. The number of executive units can vary depending on the total number of air conditioners in the system.
Connection diagram of BURR-1 and BIS-1 with signal transmission via infrared channel, with the possibility of coordinating the operation of 15 air conditioners
In addition to the device itself, the BURR-1 package includes a temperature sensor. Executing blocks are purchased for each air conditioner. Equipped with an IR probe and a double-sided self-adhesive gasket for fixing it. The thermal sensor is purchased separately.
Note that the complete set of the matching devices depends on the manufacturing plant and often includes the entire required set of temperature sensors and auxiliary accessories.
Before starting installation work, the equipment is de-energized, other safety requirements are observed.
BURR-1 has a plastic case, convenient for installation on a special metal profile - a DIN-rail, which is placed on the electrical panel, next to the circuit breakers. A 3.5 cm DIN rail is suitable for this purpose.
BIS-1 is installed above the air conditioner or directly on the air conditioner body with fixation on a self-adhesive double-sided gasket. A temperature sensor is fixed in the area of the entrance of the guide louvers. It is here that he will be able to catch the flow of cold air and determine that the air conditioner is in operation.
Also, the system requires one common external thermal sensor, which is installed in a holder on the wall in the server room at an equal distance from the air conditioners. This sensor must not be exposed to external thermal influences, for example from radiators.
If it is possible to organize the electrical wiring, the BURR-1 control unit can be installed outside the control room, for example, on a wall or even in an adjacent room.
A passport and detailed instructions are attached to the BURR-1, where recommendations for installation are given and circuits, one of the advantages of the model is the connection of the temperature sensor and power supply without observing polarity
The emitter probe is installed in such a way that it "looks" into the air conditioner photodetector from a distance of no more than 10 cm with a permissible deviation angle of 45-60 degrees.
The transmission range of a stable radio signal is 50 meters. That is, this is the limiting distance between the main and executive units. It is desirable to reduce it in order to reduce the level of interference emanating from third-party equipment.
The following installation features should be highlighted:
- lack of cable lines;
- the possibility of expanding the system;
- implementation of different redundancy schemes.
When connecting the air conditioner rotation unit, there is no need to lay a cable for transmitting control signals, which, among other things, saves space in the server room. The composition of the air conditioning system is variable.
It can include a different number of air conditioners that differ in their capacity. Developing and increasing the equipment of the server room, the company, as required, can include new air conditioners in the system (up to 15 units in total).
Rotation unit working principle
In the process of working with BURR-1 by means of radio signals at a frequency of 433 MHz, commands are transmitted to the execution units, which turn on and off air conditioners using infrared emitters, in accordance with the established settings. Air conditioners must be equipped with photo detectors. This requirement is met by most modern models, including those for household use.
The executive unit BIS-1M is usually installed on the wall directly above the air conditioner, during operation receives radio signals from the control unit and transmits commands to turn the air conditioner on and off via the infrared channel
Continuous monitoring of temperature sensors is carried out. By comparing the received data, the status of each air conditioner is determined. If the air conditioner is turned on, and the sensor installed on its blinds shows that the temperature change at the output is less than 2 C, reserve powers are turned on and an alarm is signaled.
How the setup is done
Based on the user-defined settings of the rotation control unit, the air conditioners are turned on and off. In this case, a certain sequence and specified time intervals are observed.
To enter the settings menu of the control unit, press "Enter". If the settings are changed during operation, at the moment of pressing this button, the unit can transmit commands using a previously specified protocol. In this case, you will have to wait a little while continuing to press "Enter".
Settings menu items are combined into several groups, including registration of executive units, time and temperature parameters. Information about the system operation is displayed on the display of the control unit. It is presented in the form of clearly formulated phrases and symbols. On the display you can see the type of the transmitted command and its current status, which facilitates the configuration and subsequent operation of the BURR-1.
Using the control panel, each air conditioner is assigned a number, its purpose is determined. Air conditioners are grouped depending on their purpose: reserve, rotation participants, etc.
BURR-1 front panel with LCD display and control buttons, due to its compact size, takes up little space in the switch cabinet, thanks to well-thought-out ergonomics, it is convenient for setting settings
Using the data entry panel, set the maximum permissible temperature values in the server room, the temperature connections, disconnections, alarms, and time settings related to collaboration and rotation.
The operating mode of the executing unit is determined by the change in the color and blinking frequency of the diode located at the bottom of the case. For example, when the executive unit is in normal mode and is waiting for a command from the control unit, its LED slowly blinks green.
When such a command is received, the yellow light comes on for 1-2 seconds. The execution of the switch-on command is accompanied by rapid blinking of green color. If the shutdown occurs, the LED lights up red and also blinks quickly.
Having set the settings and wanting to exit the menu, press the "ESC" button. If no buttons are pressed for 4 minutes, that is, completely inactive, the exit will be performed in automatic mode.
If there is no button press because the command is being recorded and the IR signal is awaiting, there will be no automatic exit. Please note that when performing some operations, pressing "ESC" will result in an exit from the menu, in which the changes made to the settings will not be saved.
Regardless of the model, the setup process is intuitive, as can be seen from the photo of the matching operation of air conditioners SRK-M3 with indication of control buttons, sensors, service and information LEDs
When the unit is in the setting mode, the rotation control is suspended, although all the timers are running, counting down the operating time of each air conditioner group and the rotation time.
The process of configuring the rotation control module is described in detail in the instructions attached to it.
Equipment care rules
To ensure normal operation and long service life, the control and executive units are regularly maintained. Once every 3-4 months, the reliability of the fastening, the quality of the connections, and the serviceability of the connectors are checked. The terminal blocks and outer surfaces of the enclosures, as they become dirty, must be cleaned of dust, avoiding the ingress of debris and foreign objects.
Selection factors and additional functionality
There are different models and modifications of air conditioner rotation and redundancy units on the market, differing from each other:
- by characteristics;
- by a set of functions;
- by the method of installation;
- by the type of management.
The control signal can be transmitted not only via the infrared channel, as in the BURR-1, but also via wires. The complete set differs in the number of temperature sensors. The sensors themselves can operate with one or another error, which, to a certain extent, determines the response speed of the rotation unit. Also pay attention to the timer error. This and other data must be indicated in the accompanying documentation.
When choosing a coordinator, the requirements for the air conditioning system, its composition and configuration are taken into account. So, for air conditioners without photodetectors, you can choose devices with a wired type of control. An important criterion is the functionality of the device.
Rotation units with a wide range of functions are available today. In addition to performing their basic tasks, these devices automatically restart air conditioners, the operation of which has been stopped due to a lack of power. Do not allow turning off the air conditioners if a person accidentally gives such a command from the remote control.
One of the simplest redundancy units for two air conditioners, on the left are buttons for registration and settings, on the right are buttons for switching to operating and service modes
When the alarm loops are connected, messages about emergency situations are transmitted. For example, a fire message is sent if the temperature in the server room rises above a certain value (usually at 69 ° C). The signal can be sent to the fire brigade, it is also possible to alert personnel via SMS.
Events and data from temperature sensors are recorded in non-volatile logs. Provides the ability to remotely control via RS485 and Ethernet. Supports industrial Modbus communication protocol.
After reviewing the description and technical characteristics of the device, it is worth making sure of the importance of its functionality in order to make an informed economically viable choice.
It should be borne in mind that the uninterrupted cooling depends not only on the redundancy unit, but also on the air conditioners themselves. Server rooms use precision, duct and wall inverter split systems. The latter option is most in demand, since such devices are much cheaper and take up less space.
Wall-mounted air conditioners provide adequate cooling of server rooms and, unlike precision models, can be used in small rooms
When choosing a wall-mounted air conditioner, attention is paid to the cooling capacity, which must correspond to the excess heat to be neutralized.
The air conditioning system must function in the server room regardless of the season. If the lower limit of the operating temperature of air conditioners is limited to -10 C, additional low-temperature kits are purchased.
Conclusions and useful video on the topic
Commissioning of the air conditioning system with a coordinator in the server room:
Unpacking and overview of the rotary unit for two air conditioners:
For uninterrupted, round-the-clock cooling of the server room and eliminating equipment failures rotation and redundancy blocks are used, which turn on and off air conditioners at a given algorithm. In case of failure or lack of power of one of the air conditioners, the reserve one immediately turns on. Due to variable operation, the service life of air conditioners is increased.
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