When it comes to calculating an air conditioner by area, the type of room that will be serviced plays the main role in the selection of the desired model of climatic technology. The easiest way is to choose a cooling device for an apartment, more difficult - for a server room or industrial premises that require maintaining constant temperature parameters and a certain level of humidity.
Of course, experts know better how to select an air conditioner by area, but in order to assess the quality of the services provided by the masters, the customer should be aware of some of the features of the correct calculation.
Choosing an air conditioner for an apartment or a small office
As a rule, for residential premises, buyers prefer split- or multi-split systems with an internal block of various designs. To select an air conditioner of the required power (or rather, the cooling capacity or cold power), it is not enough to know only the size of the room, you also need to calculate the volume. What else needs to be considered when choosing an air conditioner for an apartment by area, and how to make calculations?
There are special formulas in which, in addition to the area, they take into account the heat generated (or heat gains) from:
- people who are constantly there - 0.1-0.2 kW;
- constantly working household appliances - 0.2-0.4 kW for each device;
- TV and computer - 0.2 and 0.3 kW, respectively;
- windows and doorways (here it is important to take into account the side of the world where the window opens);
- roofs.
Both at the roof and at windows with doors, on average, heat gains are equal to 30-40 W / m³. The height of the ceiling can also go a plus, since with its values more than 3 meters, the power will have to be increased.
The resulting value of the required cold (Q) will be equal to the sum:
- heat gains from windows, doors, ceilings, walls and floors multiplied by the area and height of the room (Q₁);
- heat gains from people (Q₂) and all household appliances (Q₃).
To choose an air conditioner for an apartment by area, you will have to use this formula:
Q = Q1 + Q2 + Q3
But there are even simpler options that eliminate the need to multiply, add and count.
Far from being news - these are online calculators for calculating the area of air conditioning in rooms up to 70 m². It is enough just to enter all the data, and the program will give a finished result.
In practice, experts very often add another 30% of it to the nominal refrigerating capacity indicated in the manual as a reserve for the items listed above, or for every 10 m² they take 1 kW + 20% on top of the result obtained.
In general, a power reserve is always needed where the windows face the sunny side of the world or the roof is very hot.
Choosing an air conditioner for a server room
To begin with, it is worth clarifying what a server room is, and what requirements for climatic equipment exist for it.
The server room usually accommodates large-sized equipment for special purposes (telecommunications, computing facilities, etc.), which is responsible for the company's regime and its communication with the outside world. The sizes of such rooms can vary greatly - the area can be as large as 3 m², or several tens or even hundreds of meters.How to choose an air conditioner according to the area of the room in the server room so that the company's expensive equipment and the climate control unit itself do not fail ahead of time?
Very high demands are placed on climatic technology in such zones. First of all, the calculation of the air conditioning area implies year-round compliance with climatic standards:
- temperature not less than 18 ° C and not more than 24 ° C (deviations may be about 1 ° C);
- humidity in the range of 40-60% (deviations about 1%);
- dust content in the air (about 0.75 mg / m³), which is eliminated by installing a device with a powerful filtration system;
- optimal speed of propagation of air streams (0.2 m / s).
Of course, the main role is played by the air conditioning area when it comes to calculating the required cooling capacity, but even this value for the server room is obtained in a different way.
Basic calculations
The sum of the areas of the floor, ceiling and walls is taken as a basis. They do it according to the following formulas:
- the length of the floor or ceiling (L) multiplied by their width (B);
- the height of the walls (H) multiplied by their width (B);
- then the obtained data are summarized.
Thus, the total heat dissipation area is obtained.
Now the calculation of the air conditioner by the area for the server room goes according to the following points:
- determination of the total heat release of the equipment itself + additional equipment;
- determination of heat gains from:
- window openings - 0.02 kW per meter of glazing with the shadow side and 0.2 kW with the sun;
- floor, walls, ceiling - done according to the formula specified in the description of the choice of an air conditioner in an apartment by the area of the room;
- lighting devices - multiply among themselves the number of lamps, their power and the average efficiency of using electricity for lighting;
- heating devices - about 0.1 kW / m²;
- supply and exhaust ventilation - measure the air speed near each supply grille and multiply by the air section coefficient;
- people - an average of 0.175 kW per person.
To calculate the amount of heat generated by servers and other equipment, you must use the technical documentation for the equipment and add all the values or measure the current on the supply cable at the time of maximum electrical load, and then multiply the obtained values by the voltage in the network.
For example, with a current of 40 A and a voltage of 400 V, the total thermal power of the equipment will be 16 kW.
The method with measuring the current is more accurate, since the documents indicate the nominal values calculated according to the average values, which may differ by several percent from the actual working ones.
When all the data are ready, it remains only to add up the results obtained and, one might say, the selection of an air conditioner by the area of the room for the server room is completed.
Some experts simplify the whole procedure and do this:
- require from IT administrators a competent technical task with access to documentation for server equipment;
- another 30% of the received amount is added to the total heat dissipation power of the servers (heat gains from everything else are laid in them).
But this method still does not guarantee 100% accuracy, and the masters who use it act at their own peril and risk.
Air conditioning capacity reservation
As for the backup equipment when calculating the air conditioner relative to the server room area, the rule of alternating operation of devices applies here. The basis is usually laid either 50% of the reserve or all 100%.
When backing up only half, one device out of three is left as a spare. In the case of a full reservation, the number of spare air conditioners is doubled. If one or more devices fail, then the backup device takes over the operation before the arrival of specialists. Sometimes, initially, the system assumes the operation of all units in turn.
Other work organization devices
If the area of the room is large, and there are several air conditioners, then it is necessary to take into account the installation of coordinating the operation of devices - a rotation device. It ensures the uninterrupted development of the resource of climatic units by alternately switching them into operation with a specified period of time. When the set temperature rises, a spare air conditioner is connected to the operation, and if the permitted levels are exceeded, a signal is sent to the dispatcher's console. Rotation systems are used both in conjunction with dispatch systems and independently.
For the well-coordinated operation of all climatic equipment, the installation of an automatic control system will be required, which is responsible for controlling:
- climatic data;
- the work of the internal elements of the devices;
- refrigerant circulation;
- signals about dangerous situations and accidents;
- the operating time of each module and its switching.
Remote control is perfectly carried out through computer monitoring.
Which air conditioner to buy
It is often practiced to install semi-industrial splits (high-quality column, duct, wall and console) in the server room, but this is justified only in cases with small rooms. There is one advantage here - a lower price than that of professional precision air conditioners.
But most of them are not able to work all year round and 24/7. You will definitely need a winter kit so that these installations cool the room in winter at temperatures below -5 ° C outside, otherwise, in addition to obtaining low efficiency and compressor breakdown in the future, a failure in the server equipment may occur. It is often necessary to install a humidifier, and this is inconvenient in maintenance, since it requires constant filling with water.
The best solution for a server room will be a precision air conditioner, because:
- its design is designed to constantly maintain the desired temperature and humidity;
- it has a fan many times more powerful than the fan of household and semi-industrial air conditioners;
- it is equipped with a multi-stage filtration system that solves the problem of dusty electrical equipment;
- it gives out high efficiency during operation, since useful activity is not spent on condensation;
- it is fully compatible with the building microclimate dispatching system.
Among precision systems, the majority of devices have an extended power range for cold - from 5 to 100 kW. Outwardly, such air conditioners are similar to cabinets, and their installation differs little from the installation of a column or cabinet type. Depending on the needs of the room, you can choose a precision device that works on the principle of freon, water or mixed cooling.
If the choice of an air conditioner by the area of the room is made for a large server room, then, due to the listed advantages, a precision installation is preferable. Its only drawback is the high cost of construction and installation.
MITSUBISHI ELECTRIC precision air conditioners exhibit the most positive performance characteristics, LIEBERT HIROSS, DAIKIN and UNIFLAIR.
Choosing an air conditioner for a production area
In fact, the process of calculating an air conditioner based on the area of a production or warehouse premises does not differ from the selection process for a server room. It's just that instead of server hardware, there are different production units here (depending on what is produced or stored). Their total heat gain is calculated in the previous way.
In this area, precision air conditioners have proven themselves in the best way. There are also options for installing VRV and VRF systems, chiller and fan coil unit, central air conditioner.
When buying a precision installation, preference is given to custom-made air conditioners, since this is the option that can take into account all the nuances of a particular building.To do this, you need to correctly calculate all the parameters and select the most optimal characteristics of the equipment.
