Computer room air conditioning, as its name implies, is a kind of high-precision air conditioning specially used in computer room. Because it can not only control the temperature of the computer room, but also control the humidity at the same time, it is also called the constant temperature and humidity air conditioner of the computer room, and because of its high precision in temperature and humidity control, it is also called the precision air conditioning of the computer room.
The main service object of computer room air conditioner is computer, which provides stable and reliable IDC for the computer room and tests the working temperature, relative humidity and air cleanliness of the computer room. It has the characteristics of high sensible heat ratio, high energy efficiency ratio, high reliability and high precision.
Composition:
Room air conditioning is mainly composed of six parts:
1, control and monitoring system
The control system displays the temperature and humidity of the air and the working state of the air conditioning unit through the controller, analyzes the signals fed back by the sensors, and sends working instructions to various functional items of the unit to achieve the purpose of controlling the temperature and humidity of the air.
2. Ventilation system
When the functions in the unit (refrigeration, dehumidification, heating, humidification, etc. ) To deal with the air in the machine room, air flow is needed to complete the heat and moisture exchange, and the gas in the machine room needs to maintain a certain flow rate to prevent dust deposition and filter out the dust suspended in the air in time.
3. Refrigeration cycle and dehumidification system
The evaporative compression refrigeration cycle system is adopted, and the latent heat of evaporation absorbed by refrigerant is used for refrigeration. Refrigerant is the working medium to realize refrigeration cycle in air conditioning refrigeration system, and its critical temperature will increase with the increase of pressure. Using this characteristic, the refrigerant gas is compressed into high-temperature and high-pressure gas by a compressor, and then sent to a condenser for high-pressure cooling, and the gas will dissipate heat and condense into liquid at a higher temperature. The high-pressure refrigerant liquid passes through the throttling device, so that the pressure drops rapidly and then reaches the evaporator.
The basic refrigeration system is mainly composed of four parts, compressor, evaporator, condenser and expansion valve.
Dehumidification system generally adopts its own refrigeration cycle system, and adopts reduction under the same refrigeration capacity.
4. Humidifying system
It is realized by heating water to form steam through equipment such as electrode humidification tank or infrared humidification lamp.
5. Heating system
As heat compensation, heating is mostly in the form of electric heating tube.
6, water cooling unit water (glycol) circulation system
The condenser of the water-cooled unit is located inside the unit, and the circulating water cools the refrigerant vapor through the heat exchanger and condenses into liquid. Because of the large specific heat capacity of water and the small volume of condensation heat exchanger, the three-way valve can be controlled by adjusting the pressure according to different backwater temperatures (or the electric control valve can control the water passing through the heat exchanger to control the condensation pressure. The power of circulating water is provided by the water pump. There are several common cooling methods for heated water, that is, sending the water to the closed coil of dry cooler and returning after being cooled by fan. Dry cooler works stably and has high reliability, but it needs cooling coils and large volume fan. There is also an open cooling method, that is, the water is sent to the cooling tower for spraying, and then returned by evaporation and heat dissipation of the water itself. This method needs to replenish water to the system and soften the water, and impurities such as dust in the air will also enter the system. In severe cases, it will block the pipeline and affect the heat transfer effect, so it needs to be cleaned regularly.
Features:
The role of air conditioning in computer room
Independent refrigeration system, independent heating system, independent humidification system
Independent dehumidification system
Air filtration system in high-demand computer room
monitoring function
MTBF (mean time between failure) > 65438+ million hours
Specific features:
1, annual refrigeration
Due to the high calorific value of the computer room, too high calorific value will lead to a series of problems. Some IDC rooms have a calorific value of more than 300w/, so they are cooled all the year round.
It should be mentioned here that the air conditioner in the machine room also has a heater, but it is started during dehumidification. When dehumidifying, the outdoor air temperature should be relatively low, so as to prevent the room temperature from dropping too fast (it is required that the temperature change of the machine room should not exceed 10 minute and the humidity should not exceed 5% per hour).
2. High sensible heat ratio
Sensible heat ratio is the ratio of sensible cooling capacity to total cooling capacity. The total refrigeration capacity of air conditioner is the sum of sensible cooling capacity and latent heat, in which sensible heat refrigeration is used for refrigeration and latent heat refrigeration is used for dehumidification. The heat in the machine room is mainly sensible heat, so the sensible heat of the air conditioner in the machine room is relatively high, generally above 0.9 (ordinary comfortable air conditioner is only about 0.6). Large air volume and small enthalpy difference are the essential differences between room air conditioners and other air conditioners. The air volume is large, and the exhaust temperature will not be too low, which can increase the number of air changes in the computer room and is beneficial to the operation of servers and computers. If the temperature of the computer room changes too much in a short time, it will cause the server to run incorrectly. If the humidity of the computer room is too low, it will generate static electricity (static electricity can reach 10000 volts when the humidity is 20%).
3. High energy efficiency ratio
Energy efficiency ratio (COP) Even if the conversion ratio of energy and heat, 1 unit energy is converted into 3 units of heat, COP=3. Because most air conditioners in computer rooms use scroll compressors (minimum power is 2.75KW), the maximum COP can reach 5.6. The energy efficiency ratio of the whole machine reaches above 3.0.
4, high precision design
The air conditioner in the computer room can not only adjust the temperature, but also adjust the humidity with high accuracy. Computers, especially servers, require very high temperature and humidity. If the change is too big, the computer calculation may be wrong, which is very unfavorable to service providers, especially the banking and communication industries. Generally, the requirements of air conditioning in computer room are temperature accuracy 2 and humidity accuracy 5%, while the temperature accuracy of high-precision air conditioning in computer room can reach 0.5 and humidity accuracy 2%.
5, high reliability
The most important thing in the computer room is reliability. In order to run trouble-free for 8760 hours a year, reliable components and excellent air conditioning control system in the computer room are needed. Generally, most computer rooms are N+ 1 backup. If there is a problem with one air conditioner, other air conditioners can take over the whole system immediately.
When we rent a server, the service provider will ask which U to choose. What does the u in this stand for? Because I want to share the server, but I don't understand the concept of U, I feel embarrassed in an instant. I often see the phrase "a new generation server with a thickness of only 1U" in the advertisements of PC servers. Let's see what u means in the server. 1U, 2U, 4U, which server is better for the blade machine?
What does the "u" in the server mean?
In the field of servers, "U" refers to the thickness of rack-mounted servers, which is the unit representing the external dimensions of servers and the abbreviation of unit. Detailed dimensions are determined by the American Electronics Industry Association (EIA) as an industry group. The basic unit of thickness is. Centimeter. 1U is 4.45cm, 2U is 8.9cm, which is twice as much as1u. In other words, the so-called "1U rack server" is a product whose appearance conforms to EIA specifications and its thickness is 4.45cm.
The reason for specifying the server size is to keep the server in an appropriate size to be placed on an iron or aluminum rack. There are screw holes for fixing the servers on the rack, so that they can be numbered with the screw holes of the servers, and then fixed with screws to facilitate the space required for installing each server.
Server size specification:1u = 4.45cm 2u = 8.9cm3u = 4.45cm * 34u = 4.45cm * 4.
In order to save space, the current servers are all flat, and the specified dimensions are the width (48.26 cm = 19 inch) and the height (multiple of 4.445cm) of the server. Because the width is 19 inch, the rack that meets this requirement is sometimes called "19 inch rack". The basic unit of thickness is 4.445cm. 1U is 4.445cm, and 2U is twice that of 1U.
1U equals 1.75 inch (1 inch equals 2.54 cm), that is, 1U equals 4.445 cm. The so-called "1U PC server" is a product with a shape conforming to EIA specifications and a thickness of 4.445cm. Products designed to fit into a 19-inch cabinet are generally called rack servers.
Putting the server on the rack is not only beneficial to daily maintenance and management, but also may avoid unexpected failures. First of all, placing the server won't take up much space. Rack-mounted servers are neatly arranged in the rack, which does not waste space. Secondly, connecting wires and the like can also be neatly placed in the rack. Power cables and network cables can be laid in the cabinet, which can reduce the accumulation of connecting wires on the ground, thus preventing accidents such as kicking off wires.
1U, 2U, 4U, which server is better for the blade machine?
Our common rack servers are 1U, 2U and 4U. At present, the more popular servers on the market are 1U and 2U, so which is the best? In fact, there is no best product, only the most suitable product, and each product has its own characteristics. As long as we fully understand the products and our own needs, we can easily choose the most suitable machine. So what are the advantages of 1U and 2U servers? How to choose a server? What is the basis for enterprises to choose servers?
Advantages of 1U server: saving space and low hosting cost;
Advantages of 2U server: large expansion space and good heat dissipation;
If your server needs to load more than 4 hard disks, it is a good choice to choose 2U server. If the server doesn't need to load too many external accessories, then the 1U server is fully competent. The 1U server is most suitable for computer room hosting, and it can well handle the heat dissipation problem of the 1U standard server in the constant temperature and humidity environment of the professional IDC data center.
U is the height of the server chassis, and 1U is equal to 4.45cm, so 3U is 3x4.5CM With the rapid development of enterprise informatization, the demand for servers is increasing. In the limited computer room space, how to plan and implement it reasonably is very important for us. Because of its flexible configuration and high computing density, rack server has advantages over tower server in saving energy cost, maintenance cost and environmental cost. These advantages provide a broad development space for the construction of large and medium-sized information systems and 1U servers.
So what is a 1U server?
The so-called 1U server is a high-availability, high-density and low-cost server platform, which is specially designed for special application industries and high-density computer environments. They can start their own operating systems through the local hard disk, such as Windows NT/2000/2003, Linux, Solaris, etc. , similar to a standalone server. In this mode, each motherboard runs its own system, serving different designated user groups, and there is no correlation between them. However, we can still use system software to assemble these motherboards into a server cluster.
The height of 1U is limited, and there are special requirements for accessories, which will increase the overall hardware cost and the difficulty in selecting accessories. It can be said that 1U server is a high-availability, high-density and low-cost server platform, which is specially designed for special application industries and high-density computer environments.
1U server has limited space, scalability and heat dissipation, so it is generally impossible to achieve too complete equipment expansion. Compared with 1U server products, 2U is medium and high, and its expansibility (hard disk storage, expansion slot, power supply) has been obviously enhanced. Its heat dissipation has also been further improved. If server hosting service is adopted, the hosting cost of 1U server is higher than that of 2U server. However, the specific choice of several U servers needs to be based on the type and scale of the website to avoid the waste of server resources and funds.
/kloc-specific specifications and cabinet selection of 0/u, 2u, 3u and 4u tower servers!
1u, 2u, 3u and 4u tower servers have more specific specifications and cabinets to choose from. Because this is just the appearance specification, the configuration inside depends on you. However, the height of rack chassis should be considered when adding expansion cards, and 2U is two such heights. And so on, 5mm, which is the standard length of rack chassis.
So the lower the better. The tower chassis is not necessarily the same, so the width is the same. The hosting price is determined according to the height, that is, a few u. You must understand the meaning of this U, and there are longer special cases, such as the case with two motherboards, with a fixed width of 430 mm
Take 1U standard:
His dimensions are: length: 550mm, width: 430mm, height: 43, the short one is 1.2M, the high one is several meters, and the big one is ordinary. There are two towers next to it, called twin-tower chassis. The height depends on several U's. You can understand that the height of a U is 43, but there are also long boxes. The standard long box is 650mm long. 5 mm. It depends on how many machines you want to put, because rack chassis is for cabinets. The visual height is about the height of an ordinary optical drive.
The tower chassis has no fixed size. When it comes to configuration, the width of the cabinet is the same, depending on the specific situation. The standard cabinet is 800*600, and 1U 2U 3U does not have these heights. Only rack servers are 1U 2U.
The choice of cabinets depends on your own needs. Generally speaking, a tower server of 2000 mm*600mm* 1000mm or 2000 mm*600mm*900mm is generally 4U.
Summary:
The u of the server is not two CPUs! Moreover, U is not the patent of the server, it is originally a rack structure for communication exchange, referring to the rack of the server. At present, it is used as an unofficial standard in frame structure, including the specified screw size, hole spacing, track marking and so on.