How to calculate air conditioning?

Buying an air conditioner is far from easy. You need to decide on the functionality, design and brand, and you also need to know how to calculate the air conditioner so that its performance matches the volume of the room. Not only cooling efficiency, but also the working life of the unit depends on the last parameter. After reading this article, you will be able to calculate the split system in the most accessible way for you.

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How to calculate air conditioning? - Three available methods

In fact, there are few ways to calculate the cooling capacity of an air conditioner:

• Using special online calculators - they are posted on the portals of manufacturers and dealers who sell household appliances.
• By the criterion of the area of ​​the room.
• Calculate air conditioning using formulas that take into account the volume of the room and the heat sources inside it.

Important! There is a special thermophysical calculation, but it is quite complicated for an uninitiated user. As a rule, design engineers use this technique for calculations.

Using an online calculator

The essence of this method is as follows. Online portals of home appliance manufacturers have online calculators. Using them, you extremely simplify the process of calculating the cooling capacity of the unit.

You just need to fill in the required fields:

• room parameters;
• desired air temperature;
• number of heating appliances.

Then, by clicking the calculation button, you will get the desired wattage figure, which you can safely take as a basis. This is a fairly simple and quick way. However, it has a significant drawback - universality. We have no idea what heat input from different sources is included in the program. Sometimes the power value is obtained with a large “margin”, and this is an additional cash cost. For this reason, it is advisable to verify the resulting figure using calculations by other methods.

Room space calculation

This technique is often used by sales representatives. How to calculate air conditioning by this method? Its essence is as follows. The following statement is taken as the basis: with a ceiling height of 3.0 m per 100 square meters of living space, 100 W of cold power should be allocated.

Important! For example, if the room area is 20 squares, then the desired wattage is 2000 watts.

With a higher ceiling height, the specific cooling capacity indicator is selected in accordance with the table:

• 3.0-3.4 m - 0.120 kW / square meter.
• 3.4-4.0 m - 0.140 kW / square meter.
• More than 4.0 m - 0.160 kW / square meter.

A more accurate calculation is obtained if we take into account the margin of power spent on compensating for thermal receipts from people in the room and from household appliances. It is customary to use the following conditional values ​​of the released amount of heat (in terms of wattage):

• Man - 0.3 kW.
• The unit of household appliances is 0.3 kW.

Important! For example, if a person who works on a computer is constantly in the room, then another 600 watts must be added to the ones calculated 2000. As a result, we get 2600 watts.

If you calculate the air conditioning in this way, we get overestimated figures. The amount of heat generated by a person is:

• at rest - 0.1 kW;
• at light load - 0.13 kW;
• when performing heavy work - 0.2 kW.

Calculation of refrigeration capacity per cubic meter

The basis of this calculation is the value of the specific amount of cold per 1 cubic meter of room volume. The calculation is especially accurate if the square of the room does not exceed 70. Denote the specific power indicator by q.

Its meaning is accepted:

• for shaded rooms - 30 W / cubic meter;
• for rooms with average illumination - 35 W / cubic meter;
• for rooms located on the sunny side - 40 watts / cubic meter.

Multiplying the specific value of the wattage by the volume of the room, we obtain the value of the required power for this room.

Since household appliances and people are located in the building, the values ​​of wattage are added to the resulting figure:

• for a computer - 0.25-0.3 kW;
• for household appliances - 30% of the nominal value of power consumption;
• for a person - 0.13 kW.

Important! For our example (suppose the height of the room is 2.7 m).

Then the volume of the room will be 20x2.7 = 54 cubic meters:

• For a room with average illumination, the specific cooling capacity corresponds to 35 W / cubic meter.
• If there is a person with a computer in the room, then the air conditioner wattage will be: Q = 35x54 + 130 + 300 = 2320 W.

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How to calculate air conditioning taking into account additional factors?

There are a number of factors that affect the indoor climate. In order not to be in a situation where the split system "plows" around the clock without shutting down, you need to consider such factors:

• The room is located on the top floor.
• The presence of a translucent roof or panoramic glazing.
• A large number of people in the room (this is true for offices).
• Frequent airing of the room.
• A large number of units of office equipment or household appliances.

Important! In these cases, the calculated wattage is increased by applying factors of 1.2-1.5.

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Making the final choice

So, in the above calculation, the calculated value of the power of the refrigeration unit is 2320 watts. But we must also take into account that the equipment, working 24 hours a day, will quickly fail.

Important! To operate the air conditioner in a gentle mode, it is necessary to provide a power reserve. Its value, as a rule, is from 15 to 20 percent of the calculated value. In our case, it will be: 2320 x 1.15 = 2670 watts.

In the technical documentation for the product, you can see the characteristic indicated in British units of heat. Here is the correspondence of the air conditioning capacities in Watts and British units:

• 2100 W - 7 BTU - for rooms up to 20 “squares".
• 2600 W - 9 BTU - 20-25 m2.
• 3500 W - 12 BTU - 25-35 m2.
• 5200 W - 18 BTU - 35-50 m2.
• 7000 W - 24 BTU - more than 50 m2.

Important! This information can be used for approximate calculations of the refrigeration capacity of a split system.

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Stock footage

The methods described in the article allow you to calculate the conditioner very, very approximately. If you want to make an accurate calculation, but are not sure of your own knowledge, it is advisable to contact a specialist.