Cooling of server cabinets is the most important task that allows you to extend the work resource and avoid the failures of the electronics of the server center. In recent years, new developments have been actively being implemented, helping to make cooling for server cabinets more efficient. The cabinet itself is a standard means to protect equipment from any hosting or telecommunications organizations. Most of them are equipped with powerful cooling systems consuming a large number of Electricity. It follows that one of the actual moments - make cooling more economical.
Many organizations solve this problem by installing conventional air conditioners indoors with equipment placed on open racks. On the one hand, this solution seems profitable, but with long-term operation it turns out that the cooling of server cabinets of several cubic meters is much more profitable in economicly economicalWhat air conditioning is full of room.
5 reasons to purchase systems cooling rooms from Aquilonstroymontazh
- Using the technologies of the adjustable gas environment
- Maintaining specified temperature mode at each point of the room
- Accurate distribution of air flow at a given temperature.
- Selection of equipment based on the existing heat insulation
- Comprehensive use of cooling and ventilation
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Modern technique - a standard 19-inch wardrobe on the walls is equipped with an air conditioning system, and the power supply is placed outside this design. The cooled air enters through the side panel, goes to the front, and then headed to the rear wall, at the same time cooling the equipment. Warm air It is displayed out. Analogy cooling systems are different power, modifications, various accommodation schemes apply. However, the principle of operation remains unchanged in all cases. If the cabinet has large sizes, then whole complexes of fans can be mounted for greater efficiency. It is not less rarely using row models with a capacity of up to 25 kW. The principle of their action is similar to those described, except that there is no external block. Fans guide the air to the heat wall, heats up and output. This allows you to maintain inside the stable temperature. There are more progressive methods. For example, for example, the use of microchannel cooling panels placed on the rear panel. In this case, the fans are not used, so the noise level and the consumption of electricity is significantly lower. The cooling agent is the usual water located in the temperature wall channels. The cooling of server cabinets is not only important, but also quite complicated in solving the problem requiring a professional approach. Specialists of Akvilonstroyontazh will help you competently resolve it. We carefully follow all changes in technology, whenever possible, we introduce them into our activities and can guarantee you that we will cope with the tasks at a high level.
- Rittal air conditioning systems provide the necessary microclimate and protection of telecommunications equipment installed in the cabinets.
- This includes cooling sensitive electronics in distribution cabinets and control cases of industrial processes, as well as racks for servers and network equipment.
- All this is a comprehensive solution based on Rittal products.
- Ideally combined and controlled cooling is environmentally friendly and energy efficient equipment.
- Chillers Toptherm for wall mounting Perfectly mounted in the door or side wall of the distribution cabinet.
- They provide centralized and economical cooling of water and submitting it in all. On air-water heat exchangers. Condenser with nanofind in standard version.
Rittal air conditioners - efficient equipment cooling
Being a leading manufacturer of equipment for data centers, Rittal responsibly approaches systems that ensures the effectiveness of the main nodes. One of the main factors of stable operation of information and network devices is to maintain the appropriate temperature level. For these purposes, Rittal air conditioners are used.
Cooling systems are represented by two types of devices: wall and ceiling, which differ at their place mounting relative to the surface of the cabinet with the equipment. Cabinet air conditioners can be mounted both inside and outside. The total cooling power of such devices varies from 0.3 to 4 kW.
Industrial refrigeration equipment in Moscow
Refrigerating units function due to cooling air located in a closed case. Thanks to the powerful ventilation system, air flow circulation and its forced cooling is provided. Due to the maximum removal of the input and outlet holes, the intersection of warm and cooled flows is excluded, which significantly increases the efficiency of the process. The layout of wall air conditioners Rittal is represented by several types of enclosures, which allows you to install equipment with maximum convenience.
It is especially worth noting a unique device of the condenser. Passing through yourself a significant amount air masscontaining dust and moisture elements, such capacitors are subjected to significant pollution. In order to minimize this phenomenon, Rittal has developed a special Rinano nanoocryment, which, due to its structure, has water, oil and dirt-repellent properties that prevent surface contamination. With the power of the device more than 1 kW, the leading condensate forms is activated by using an electric evaporator.
Server Cabinets with cooling
Cabinet air conditioners are easy to install and disassemble (in case of repair work). The package includes fasteners that are attached to the holes made by the accompanying template. Power connection is carried out through a ready-made terminal block. The air conditioners installed with the cabinet look harmoniously due to the similar material of the housings and the color of the coatings in accordance with the RAL 7035 standard.
You can choose effective and reliable Rittal air conditioners from the provided directory and immediately make an order online.
Group of Companies "MEL" - Wholesale provider of air conditioning systems Mitsubishi Heavy Industries.
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10 years ago, the author of the article happened to be a witness to one situation. The server organization was half a cabinet isolated by fiberglass. Outside the window was a winter frosty day, battery central heating I could not cope, and the IT officer opened the door of the server and turned off the air conditioner to heat the room from the equipment. An hour later, the main server of the organization with the ERP system turned off. And not just turned off, but the 2 expensive SSD disk failed. More than a hundred employees were sitting afternoon afternoon, which went to recover data from reserves. And if there were no archive .. In general, why the server is air conditioner - after that everyone knew.
Cooling options for server.
Air conditioning for large server. The most expensive, but not always the optimal way.
The word "precision" is immediately associated with accuracy. Alas, most of the "precision" server air conditioners are supplied with on-off compressors, and there is nothing to do about exactly maintaining the temperature, there are 2-3 degrees at best.
The next minus is noise. Conventional Precision Conditioners for Server is a monoblock with a remote condenser. Noise from the compressor is added to considerable noise of the evaporator fan. Well, when the server is a highlighted uninhabited room. But working in a room with a working "precision" (and it happens) - extremely tedious.
Price. The cost of precision air conditioner is two to three times higher than the semi-industrial invertor "Japanese" of the same performance.
Perhaps their only plus is a remote capacitor, potentially allowing precision air conditioner in winter at more low temperaturesthan ordinary air conditioner with a winter set.
2. Split system. The most common solution for cooling server rooms, at the same time universal, affordable and inexpensive. The smallest "server", which was seen by the author of the article - the cabinet made of fiberglass with a size of 2m * 1m * 0.4m, located in the room of the Aytichnikov. Naturally, in addition to the household wall split, it was impossible to put anything.
Most of the organizers of organizations still understand the risk of data loss on servers, and buy Japanese air conditioners for the server room. Although the main trend russian market The cost of the average cost of air conditioners begins to appear here.
It is preferable to install a semi-sensitive air conditioner for the server with a winter set, because in the half-one, even small denominations from 9000-12000 BTU, an increased margin of safety is always laid: a more reliable compressor, an enlarged area of \u200b\u200bheat exchangers, more protective functions.
3. Supply ventilation in winter. One of the options for free-cooling system. The essence of the system - a set-up supply installation is assembled, and control dampers are controlled by the influx of outdoor cold air. Usually combined with a split system (for work in the summer). The main plus is a free street cold replaces air conditioning in winter, saving on electricity and a split system resource. Minus - not everywhere can be installed. Such systems are often used, for example, at base stations of cellular communication.
Calculation of air conditioner for server.
It was possible to see situations where the air conditioner power for the server was chosen on the basis of the area of \u200b\u200bthe room, as in the apartment. With predictable result. Of course, the calculation of the air conditioner for the server should be built on heat-flow from the equipment. Ideally, you need to know the tributaries from each server / cabinet. But it is often not indicated in the documentation. Then the easiest way is to calculate the power of the power supply blocks, or at least the power of uninterruptible power supply. It turns out the numbers with a margin, but it is better than making a choice of server air conditioner with less productivity.
The following choice is the location of the indoor unit. Since the heat from the cabinets rises up, you can immediately dispose of it with an internal block, a sub-combine or cassette type. But there is a danger that when unscrupulled installation or maintenance, the drainage can flow from the inner block down. Therefore, the internal block of the server air conditioner should not be located directly above the server or any electrical device. It is best when the block is located slightly away, and the flow of cold air blows right on the equipment.
Air conditioning problems in winter.
1. Frozening compressor oil. Even polyester oils used with Freon R410A, at low temperatures will be stuck, kinetic viscosity and lubricating properties deteriorate in winter. Accordingly, at the time of launch, the compressor starts to work "dry", an increased current occurs, increased friction of the compressor parts, in the worst case, the compressor can simply be sworn.
2. The compressor oil is absorbed with freon. The longer the air conditioner is turned off, the large quantity Freon is dissolved in oil. At the time of launching Freon in the compressor boils and goes into the pipeline along with oil particles. A situation is possible when the share of the oil went to the track will be so great that the compressor will have to work "dry".
3. ON-OFF split systems, the most common server air conditioners, the exterior fan is constantly operating at the maximum rotation speed. As a result, already at zero temperature on the street, the performance of the server air conditioner drops by 30-40%. And at negative temperatures, freon consumption will fall so much that the compressor overheating may occur, while the cooling capacity of the air conditioner will fall to a minimum.
4. Often the split systems drainage drainage is made on the street, and not in internal system sewage. Accordingly, when the air conditioner is operating in winter, the drainage tube without heating will simply leave, and the water will flow from the inner block.
To avoid all these problems when operating air conditioning in winter, install
Winter air conditioner set.
The standard winter set of air conditioner includes three elements:
Compressor Carter Heating Cable. Usually its length is 0.5 m and power 30-50W. It is installed at the bottom of the compressor, it is best to install on an exemplary border of oil and freon to minimize their mixing. A common error is the connection of this heating on the compressor power terminal. The problem is that heating will be turned on only simultaneously with the launch of the compressor, i.e. When it is already useless. Therefore, the heating of the compressor should be included on a separate, constantly detected line 220V.
Some Japanese manufacturers write in the catalogs that in their compressors the constant heated oil is carried out by stator windings. However, on all these blocks, they themselves continue to put ordinary tape heating, which hints ..
Drainage heating cable. Dress up on a drainage tube (in the case when the drainage is derived out).
. It is an electronic unit, included in the breaking of the fan of the outer block. Its purpose is to maintain a constant condensation temperature, adjusting the fan turnover from 0 to 100%, depending on the testimony of its own temperature sensor, which is usually intended in the middle of the capacitor.
There are more complex condensation regulators, for example, with a user-adjusted temperature, or regulating no temperature, namely the pressure of condensation. But, in view high Pricethey are small asked.
Such a winter air conditioner set is put on on-off models, the most common due to their cheapness. But in recent years they begin to appear
Inverter air conditioners in server.
The main difference in inverter air conditioners is smooth adjustment of the compressor revolutions. At the same time, the fan of the outdoor unit may be ordinary, unregulated. Accordingly, when choosing a winter air conditioner, it is necessary to check this nuance.
Pluses of inverter air conditioners are indisputable: less power consumption, no launcher, increased efficiency (in incomplete download mode), increased peak performance, more accurate temperature maintenance.
The main argument of opponents of inverter air conditioners in server rooms is their technical complexity and potentially less reliability.
With the first objection, it is impossible to disagree, but why should it be considered a minus? More control functions, feedback with all sorts of sensors to adjust the system under the change in the external environment - this is just an advantage.
Increasing the number of system components potentially increases risks, it is true. But inverter technologies have long been worked out, and serious manufacturers are not less reliable than outdated on-off systems. Even the first multizone systems with inverter compressors still work well at the continuation of 15 years. And since then, technology has grown qualitatively, not to mention the accumulated experience and elimination of "childhood diseases". For example, Mitsubishi Heavy has the number of compressor failures in the KX4 series decreased compared to the KX2 series 10 times!
Inverter air conditioners in the server are possible individual problems with protective functions.
Part of the protection, for example, the system failure to join at temperatures below -15 / -20c (on the outdoor temperature sensor), you can refine or "bypass" directly on the object.
Another part of the protective functions under normal conditions is difficult to turn off, for example, protection over the low pressure sensor or evaporator temperature. If the installation region of the server air conditioner is frequent temperature is below -35С, it is better not to risk the server and select the option of precision air conditioner with a remote condenser or supply ventilationIn extreme cases - to install the outer block of the Split system indoors ( flight of stairs, attic ...).
In any case, the Japanese manufacturers have already started shooting from the production of ON-OFF series of split-systems, for example, Mitsubishi Heavy Industries has been producing only inverter semi-inverter for several years. Therefore, even the opponents of the transition to invertor air conditioners in the server there are no alternatives, albeit after two or three years.
What are overlooked by experts from air conditioners.
1. All cooling values \u200b\u200bin service manuals are indicated for internal parameters: temperature 27c, humidity 50%. However, in server air conditioners work on maintaining a constant temperature of 18-20s. At this temperature, the explicit cooling capacity of the block falls by 20-30%.
To avoid problems with the lack of cold, it is necessary to consider the explicit productivity at 18c.
2. The internal unit is calculated by the manufacturer at the temperature of 27c. When only 18c comes to the evaporator, the probability of incomplete evaporation of freon occurs. Especially risk in winter air conditioners ON-OFF with a capillary tube, in inverters with EEV this risk is less. Freon's unrearfection will result in refund of the refrigerant in the compressor in the liquid phase and the breakage of the compressor. It is believed that the "wet stroke" should dampen batteries in front of the compressor, but in practice they do not always help.
To prevent the wet stroke and the bay of the compressor, it is possible to install the inner block to one size size more exterior. For example, the internal block 9000 BTU, and the outdoor 7000 BTU.
3. When the air conditioner is operating on cooling indoors, moisture from the air is constantly removed. If the room is purely technological and does not have supply ventilation, air humidity may fall up to 30%. At the same time, the risk of damage to the electronic electricity is raised sharply. The most sensitive to this problem ATS and large data centers, where it is recommended to maintain relative humidity not lower than 50-60%.
If the server will be installed electronic equipment, sensitive to electrostatic discharges, it is necessary to provide an air humidification system.
That IT-specialists are missing.
1. Rotation of air conditioners. Even the best equipment can suddenly fail. For example, due to hidden installation defects, problems with power supply or human factor. To minimize risks in serious server (for example, in banks), an additional server air conditioner is always put. Usually there are two air conditioners, each of which is capable of cooling the server alone, but they work alternately. In the case when the first air conditioner does not cope with heat flow or is generally defective - the second is automatically turned on.
Air Conditioners Mitsubishi Heavy Industries The air conditioner rotation feature is supported by the RC-EX1 wired remote control, which is possible to connect to all semi-industrial models, as well as the wall inverters of the household series.
Managing the rotation of air conditioners of other brands is possible to provide a separate device, the "air conditioner rotation unit". Universal rotation blocks are divided into two groups:
1) The control is made by the "interrupt phase". The power cable is started in the rotation unit, and then connects to the air conditioner. The rotation unit, according to the signal sensors and the time relay signals, simply disables or restores ~ 220V on the backup air conditioner. Accordingly, the air conditioner must support the "Autorsatar" function.
2) more elegant solution - imitation of the IR conditioner conditioner. Compact IR diodes are attached to the IR receiver of the indoor unit, which (via wired or radio channel) are received by commands from the rotation unit. Usually simulate only IR signals on and off for this split system, respectively, mode and temperature parameters must be pre-set from the remote.
In large server, such air conditioners can be more than two, and they can work on any given cycle, for example "five three-reserved workers", and working and reserve alternate with each other during the day.
2. Remote monitoring. Modern inverter air conditioners can be connected to the Internet in bilateral mode, receive commands from the user and report on the status of work and errors.
Economy. The wired console is connected via USB to a computer / server, a driver program is installed, and an IT specialist can monitor the server conditioner and control the settings. Accordingly, through a remote desktop, it can monitor the temperature in the server from anywhere. Such opportunities shall provide, for example, wired remote RC-EX1 in Mitsubishi Heavy air conditioners.
Tablet or smartphone. A separate Wi-Fi module is connected to the server air conditioner, which is associated with the remote server of the manufacturer, and transmits data on its work. The IT specialist installs a special application (iOS or Android) to his gadget, and can view the logging logs of the server air conditioner, change its settings (operating mode, temperature ..), as well as receive messages about accidents and errors.
BMS or SNMP. If the building has a unified engineering communications management system (" Smart House"), Then server air conditioners can also be part of it. Standard customized modbus adapters, Knx, Enocean have all Japanese manufacturers. LONWORKS or BACnet interfaces are also possible, but the price of the question will be much more.
Mitsubishi Heavy Industries connect to BMS networks is possible both for internal blocks of multizone systems and for individual split systems, and not only a semi-industrial type, but also inverter wall blocks of household series.
Also in large server, it is possible to organize a local data collection server over the SNMP protocol, the blocks of rotation of server air conditioners with its support are available on the market.
In the second part, precision air conditioners and the use of supply ventilation will be considered in detail.
At a certain point, some enterprises are growing to the state when their internal information systems cease to fit in one server cabinet. Then the head of the IT department will have to weigh all the "for" and "against" and decide whether to build or build a server. There may be several options: from full getting rid of their own capacities and lead them into the clouds or beokes in a large data center, before the construction of its own mini (or not very mini) of the blackjack.
The process of calculations, planning and construction of the server is very responsible and expensive. It will be invested at the project stage, here, by the way, you can save if all procedures in the server, from designing to construction, will produce one contractor. The natural desire of the head of the enterprise in such a situation is to meet the minimum possible amount. And in the bayonas perceived any increase in the cost of the project. In such vertaging, it is often forgotten that, in addition to the construction of an object, its content will be followed, which, with incorrect design, can be discussed by the budget of the enterprise to another non-existent server after two or three years.
The second largest consumer resources (in this case it is electricity and consumables) in the server is a cooling system. Neither the news is that the "power" of the cooling system of the server must match the minimum of the coincidence, and at best, to exceed a couple of dozen percent peak power of all equipment installed in the server. About which cooling systems are and how to save on the operation of such systems, we will talk in this article.
Classification of systems cooling systems
The most familiar to operate and understanding are compressor air conditioners. In them, the refrigerant (in the overwhelming majority of cases - freon) transfers heat from the radiator of the inner unit into the external, where the energy dispels environment. Read more about the principle of air conditioning, you can read. Then there are liquid and combined systemsThe main refrigerant uses water or ethylene glycol, and the selection of the coolant depends not only on the operating conditions, as well as on the cooling method. And the most effective solution, in certain conditions, of course, are frekuling systems. These are exclusively precision devices that are developed almost from scratch in each particular case.Also worth paying attention to the classification according to the "form factor". Here it is possible to divide systems into two types. Household systems that we are all already accustomed to, usually installed in offices and apartments, hanging on the walls or ceiling, but may well serve as systems for cooling specialized premises. And precision systems where specialized air conditioning systems can be attributed, and, of course, all frekuling and liquid systems.
Inside precision systems, there is a systematization on the principle of action and in the method of delivery "cold" to "consumers". And if with fundamental differences is increasingly less clear, then the methods of cooling directly the devices are a great set.
Among the classical generally accepted cases, it is possible to highlight a cold room with installed racks, household air conditioners are also suitable. Classic options Precision solutions are devices with row air ducts, with cold and hot corridors, where the racks cost rows in such a way as to take the cold air incoming, for example, from under raised floor. They give the heated air into the corridors, from where it is forcibly allocated. There are also options with air ducts to each rack, where the air is supplied to each individual rack from above or below and then is also actively selected.
Nexlassical solutions a little more than a lot. It is necessary to say that they are all precision. Most solutions are a combination of the above-mentioned systems to improve efficiency and reduce costs. The scatter here is from individual air conditioners to each server cabinet to the liquid cooling of each individual server or even the processor. And also it is necessary to highlight systems with direct contact of the consumer with liquid. In this case, the server is fully immersed in special oil. Butter is odorless and absolutely does not conduct electricity. The liquid is constantly circulating inside the basins with the equipment, and passes through the cooling radiators.
Strategy
Not once it is worth thinking about the need to build a server. It is believed that for power less than 5kW, the selected server room is not needed. Usually, all the equipment is quite "will fall" in the 42-47-unite rack-cabinet, and the maximum that will still need it - this is a separate one-frame rack under the cross. All this can be burned from the "admin" or some other premises (the main thing not from the accounting) glass or plasterboard partition With a hermetic door, put a paired household air conditioner and go drink beer.But we build a server. First of all, we need to decide which cooling system we will use, and the matter is not only in price. The choice of cooling method depends on the set of factors: the power of the equipment, the location of the server room in the building, the geographical location of the building itself and even from the prevailing attitude to certain types of cooling devices and short-sightedness.
It is common that the systems up to 10kW are quite enough of a household air conditioner. It is also clear, because household split systems of greater power, firstly, it is quite problematic to buy, and secondly, their cost is approaching, and then exceeds the cost of similar precision air conditioners.
From the location of the server room in the building, the possibility of installing a system of cooling, the ability to sum up communication, air ducts for specialized systems, arrange a falsefield or to establish turbines. In case of insufficient height of the ceilings, it is impossible to arrange a falsefield of the desired depth, to install the air ducts and air of the precision system. The position in the middle of the building will create problems when laying air ducts, one of the options for a frekuling system, and the neighborhood with the Economic Department will put the cross on the construction of the server because of "Nazhumit".
The geographical factor plays one of the paramount roles and often puts the cross on frekuling capabilities if you are, for example, in a tropical belt. That is why Codo builders love the northern regions of our planet so much, because there can not use air conditioners at all.
In addition to all, some technical experts have their own very hard belief in the applicability of one system and the absolute unacceptability of other cooling options. They will be calm and confident to prove their rightness, finding the arguments "for" and looking for the shortcomings of other sentences, from real to the mythical.
As a result, pushing off from the selected strategy, we will design the device itself.
Cooling strategy with household air conditioners
You are the owner of a small server park, 2-3 racks with which will stand in a separate room. You do not have the prospects for smooth power growth and you, or do not want to bother or (which is most likely) Do not have a budget for more energy efficient and environmentally friendly solutions.First of all, decide how the rack with equipment relative to air conditioners will be located in your server. The best of the options in your case will be the installation of the internal modules of the split-system opposite the row of the racks one above one, directed to the "front" side of the open rack or a cabinet with a mesh door. Equipment inside the rack makes sense to set the side with which it takes air to cool the internal components. Some devices installed in the rack can be rebuilt or even produced in execution when they are either taken or emit air from the front side, or into one of the side walls. Think about it when buying.
Even if the growth of total power is not expected, air conditioners should be taken with a power supply, for example, taking a peak consumption-dispersion of the "hot" rack itself and by changing them, racks, quantity.
Minimum fault tolerance in this strategy - n + 1. In practice, it looks like two and more air conditioners of the same power, where "n" air conditioners can maintain the operating temperature in the server while "+1" belt or is served. Most often, two units are used in small server. To extend the resource of both air conditioners, it is necessary to use the rotation device of air conditioners. The device during certain periods of time switches to work from one air conditioner to another, tracks their launches and controls performance. At the failure of one of the air conditioners, it should automatically connect the "sleeping" and notify the responsible about the problem. It is worth noting that this function is not supported by all models of household air conditioners.
All server split systems installed in the latitudes of our country must have the so-called "Winter Set". It is a block of government, some improvement of the radiator external block The air conditioner and the heating system of the pump crankcase. Works automatically.
Fig.1. Cooling with household air conditioners.
Precision system cooling systems
Precision (high-precision) air conditioner (or other cooler) - created as accuracy to work as efficiently as possible in infrastructure with specified finite parameters. In other words, when we say "precision air conditioning", we mean that the room, and the equipment of the server, and the refrigeration unit»Developed in a project as a set of technologies that make it possible to best ensure efficiency, the safety and durability of expensive equipment.Do I need to say that devices individual design - Pleasure is expensive. The sacred wars go between adherents of different camps. Some claim that for the usual server room there is a sufficiently spray industrial version of the household air conditioner, such as, for example, Daikin (FT and FAQ series) or Mitsubishi (Series Heavy). When choosing this option, it is important to take into account such minuses as local hot air wets in corners or in units of racks that are not engaged in active equipment. No less dangerous factor - Low moisture, because, as you know, air conditioning, dries air. Dry air contributes to the accumulation of static electricity, the presence of static potential on fine electronics has a negative impact on the work of chips, and increases the risk of their destruction by the discharge. Sure, most of Factors are eliminated, but in most cases it is crutzing production. Additional fans, air humidifiers, these are all multiple refusal points, electricity costs and maintenance. Service, by the way, the same moisturizer, it's not so much costly for the means as in time. Need regular cleaning and daily topping water.
Precision, not everything is too smooth. First of all, they are very overall: freon air conditioners have dimensions of two or three full-size racks. Since humidity control is one of the main functions of a specialized air conditioner, then the internal blocks need to bring water, which is completely unacceptable for some IT Schnikov. Cold air from such aggregates is supplied to the racks through the ducts, which are conducted or under the raised floor, the most frequent and most expensive option, or under the ceiling, which implies high ceilings and imposes additional restrictions on the cable communications laying. Capacitors-coolers of such air conditioners have decent sizes, and immediately arises the question with their placement and liner of the pipe system from the inner block.
With the minuses ended, we turn to the pros. It can be attributed here: high performance, reservers only active components of the air conditioner (for example, air ducts, I think there is no point in presenting), clear control of temperature and humidity, the possibility of detailed monitoring. Pluses The following from here is the relative savings, guaranteed delivery of cold air to the consumer, support for the high density of consumers per rack (it is rather a rule if the rack is empty, it will work inefficiently and influence the entire "ecosystem"). There is a completely explaining relationship between increasing costs of air conditioning and subsequent energy efficiency.
As I said, the most common phenomenon of precision air conditioning is the corridor system where the racks are located rows and are installed so as to pick up air from cold corridors (where air is supplied with air conditioning) and give it to hot (where the air is selected by the ventilation system). The air duct of such a system most often serves as a raised floor. The panel of the floor itself is mainly solid, all cable communications are transferred under the facility from under the festival, the lattice panels are arranged in front of the rows of racks in the floor, from where the cooled air enters the front side of the rack. Doors of server cabinets with such a device are made by mesh with both ends, or or do not do at all. Then the air heated by servers is blowing in a hot corridor from where the system is suused forced ventilation. Ideally, following the principles of thermodynamics, the hood is worth it to position at the top of the hot corridor, but often do it in a raised floor to save space over the struts for laying cable communications. With relatively recently, cold and hot corridors began to make hermetic from the general room of the server. This was achieved to achieve significant savings on the dispersion of valuable cold. In the free unit spaces of cabinets be sure to install plugs, because hot air So strives to mix with chilled. This can increase the cooling efficiency in one and a half or twice.
Fig. 2. The system with open corridors is obvious to loss of precious cold air.
Fig. 3. A more efficient, system with isolated corridors.
Intel, for example, pursuing the idea as simple as possible and efficiently cool the equipment, went further and even patented a rack with an exhaust. The rack is an ordinary 19 "cabinet, but deeper analogs and has an air duct in the top cover, opening into the space of a false-brake, from where the hot air is sucked by air conditioners. The whole system, in addition to air conditioners, is absolutely passive. But at the same time, according to Intel, it is capable of cooling 32 kW Rack equipment.
Taking into account the climate of our country, the precision air conditioners have another big plus: their diagram can be improved enough to refine, adding a complete or partial liquid circuit. Using ethylene glycol as refrigerant, parallel to the air conditioner contour build another loop with liquid cooling, thereby reducing the cost of electricity, air conditioning service and increasing the service life of these. The efficiency of the glycolic contour begins at temperatures below +20 s, which even in the summer at night in Russia is not at all uncommon.
An additional liquid circuit duplicates such freon, and in principle it can work around the clock, in the day "roast" time, cooling the air conditioner compressor and the condenser, and when the outdoor temperature drops, turning into partial and complete cooling of the internal heat exchanger.
The leaders among manufacturers of precision cooling systems are Schneider Electric, Stulz, Emerson Network Power, RC Group. Among their solutions there are ready-made combined systems.
Liquid systems
The fundamental difference of liquid cooling and freon only is that in the circuit, the liquid does not change the phase state in the circuit, which is why the water and glycolic systems are equal to the power of the system in efficiency. However, liquid systems have indisputable advantages, such as capacity and versatility. In liquid cooling systems, the cooler can be both a fancoon on the roof or in the courtyard of the building and the system of heating the building itself. The liquid can cool the air in the server, and can be used as a refrigerant for a separate processor. The indisputable advantage of liquid air conditioning is a practically unlimited length of the TRAC, due to the low price of the refrigerant, for the same system it is only a plus. The most dangerous in this situation is the leakage of a conductive agent, but, apparently, it does not scare anyone. IBM in this situation distinguished himself with the construction of SuperMUC, where 40% of energy savings achieved due to the absence in the cooling system of chillers. And Google in most of its dwarves and at all use the system of its own development, where the system of cold and hot corridors is used.Another liquid system implies a server immersion in a special mineral oil. Oil - dielectric, so that the closure will not be. As for energy efficiency, according to the allegations of specialists of the same Intel, the cooling system in this case is spent by 90% less energy, and the power consumption of the servers themselves is reduced. Racks for submersible liquid cooling are already available, for example, by Sarnotjet. Racks are suitable for accommodating any servers, it is only pre-needed to pull out all the fans from them.
Fig. 4. The most liquid cooling
Another factor of universality is a huge number of refrigerant cooling methods. For example, you can cite Seawater Air Conditioning (SWAC) technology, a Google Data Center in Finland has been built on this technology. It is clear from the name that to cool the water entering the data center, the heat exchanger is used on cold waterclosed with sea depths.
The classic liquid cooling system acts as an intermediary between relatively high temperatures inside the room by the server and the cooler, which is more often a dry cooling tower and chiller, outside.
A dry cooling is a closed cooling circuit, where the fluid enters the radiator, which is forcibly blown by air. There are still wet coolies, the water is sprayed in them and at the same time blows. In the midstairs, or fancakely, the liquid refrigerant is usually only prepared by cooling to the air temperature, the chiller heat exchanger itself occurs.
Chiller is a refrigerator, it acts on Freon, cooling fluid passing through its cooler to the desired temperature.
For classic liquid air conditioning, all the same rules are true as for systems on Freon. The air cooled in the evaporator passes through consumers and selected from the server of the cooling system. Despite the fact that liquid systems are more versatile and generally cheaper in operation than freon, the effectiveness of them is lower due to the larger number of air-chiller-fluid intermediaries. Agree, not the most successful scheme.
We remove intermediaries
Direct Fryriculing is the most energy efficient way to cool the server. Of course, its effectiveness depends entirely on air temperature "overboard", but some changes in standardization and various green technologies are gradually moving the server cooling systems precisely in this direction.Let's start with the fact that the largest standardizer engineering systems, in particular, cooling and heating systems, ASHRAE (English. American Society of Heating, Refrigerating and Air-Conditioning Engineers) - American Society of Heating Engineers, Cooling and Air Conditioning, since 2004, the recommended air temperature for cooling the server has increased twice From +22 to +27 degrees S. And in 2011, amendments were made to the standard, stratifying two new class equipment for server A3 and A4, where the temperature range was increased to +40 and +45 degrees. Server manufacturers already produce such models. Although they have not yet become widespread, more and more builders are inclined to use green technologies in cooling.
For server services in our latitudes, freuciling can be if not fully replaced the classic cooling model, then a serious help in cooling in the cold season, and will also reduce the power of air conditioners.
The biggest problem of direct frekuling is the overall air pollution in the cities. It may happen that the amount, filter consumption and the power of the fans to produce them can reduce all the savings on electricity and power. This problem is solved by the separation of contours and the introduction between the heat exchanger based on a rotary heat exchanger. In this case, the filters will also be needed, but cheaper and with minimal air resistance.
Another big problem is that, with the auxiliary function of our freucolecher, it will be badly combined with household systems and is best with precision.
Of the advantages: with direct freiculant there is no risk to cut the air in the room with a server, because There is a permanent exchange of air with external environment. On the other hand, air humidity on the street can categorically not to meet the adopted humidity standards for server rooms, and here one of the main trumps of frekuling systems is coming to the aid - adiabatic cooling.
Long ago noted wet air The reservoirs are always cooler than the plains in remote from them, remember at least sea breeze. For adiabatic air cooling, it is not necessary for neither systems for reserving neither complex technical solutions. They are arranged according to the principle of wet cooling, in the heated outer air in the chambers of the nozzles, water is sprinkled, which evaporating cool and moisturizes the air. This system Not only effectively lowers the temperature of the external air, but also creates the necessary humidity. True, new systems appear in such systems. consumables - Water. Therefore, on the equal Pue (Power Usage Effectiveness), ASHRAE introduced a new WUE term (Water Usage Effectiveness (PDF)). For what corresponds to these parameters, I think it is clear to all.
As bright examples of the introduction of such systems, you can mention the data center "Mercury" in Phoenix (USA) and Facebook in Parenville (USA).
Instead of imprisonment
"So how do you still cool the small server for a couple of dozen kVA?" - you ask.The answer is ambiguous. Most readers will suit the solution from two normal household air conditioners. Those who can convince their own leadership in the need to save and introduce environmentally friendly innovations, will receive a sea of \u200b\u200bheadache and then infinite pleasure end result.
As I said, a specific solution depends on climatic conditions specific region. To perceive the climatic picture, it is best to take historical certificate to maxima and low temperature and humidity in the entire history of instrumental observations in your region or city, as well as analyze detailed data on the hottest temperatures for last years 10-20. This is more than enough to work out a clear strategy.
Despite all the advantages of freuciling, in the conditions of the middle strip, in 80 cases of 100, it is most likely to do without compressor or liquid air conditioner. In this regard, the overall idea of \u200b\u200bbuilding a "big" energy efficient server is as follows:
- This room with a precision cooling system. Indoors are arranged raised floors for the supply of cold air, with a division into cold and hot corridors, isolated from the general room by the server to ensure a clearer heat exchange.
- Most of the time, the system operates on a direct freuciling, an adiabatic cooling system is connected with an increase in the temperature of the external air. Upon exceeding the permissible norms on the humidity temperature, the system of compressor or liquid cooling is connected, i.e. air conditioning.
It is worth paying attention to the fact that such a system will not be able to work without adequate and detailed monitoring of the state of the inner medium. Monitoring the temperature in cold and hot corridors, air humidity inside and outside, the presence of water in the adiabatic system, leak control. To do this, there are monitoring devices capable of publishing data from various sensors via Ethernet or WiFi. They are presented in the form of boards, enclosures and products for installation in the standard 19 "racks. For example, Netping is already equipped with a built-in GSM modem with an SMS module that can notify the significant changes in the parameters or the sensor triggering not only the responsible cooling system nodes, but also You personally.
In addition, all this data is not only possible, but also need to be entered into a global monitoring system, for example, Zabbix, where, according to schedules and samples, you can analyze the temperature map of the server, correlate changes inside the server and outside. Automate the creation of incidents based on the totality of indicators, and not on some one.
All this will allow you to rebuild the cooling system for maximum efficiency and prevent its breakdown.
Unfortunately, in one small article it is impossible to thoroughly work the topic of cooling the server. On the one hand, it may seem that freiculing is a way out for everyone, but in fact, this is a fairly risky enterprise. The story knows decently the number of epic situations when whole centles were outlined due to errors in designing and insufficient attention to detail. The best, though more expensive, is a solution that implies the duplication of standard cooling systems alternative.
Large codes, and incessant noise in server.