HVAC in Los Angeles can be found in offices, public spaces, and many apartments. Now, everyone has the opportunity to buy an inexpensive air conditioner. The capacity of split systems in houses and apartments is enough to cool or heat large rooms, up to 30-40 sq.m.
In this article, we will tell you in detail how to determine the capacity of air conditioners based on the
area of the room and show an example of calculation.
General information
Earlier, we told you how to choose air conditioners depending on their type and purpose.
Now that you know exactly what kind of air conditioner you need to solve your problems, you must move on to the next step – choosing the capacity.
The capacity is selected depending on the area of the rooms in which the devices will be used. It is measured in kW (kilowatts), while the area is measured in sq m or m2
(square meter).
Based on the volume of the room and some other parameters, you can quite accurately determine the required capacity. The standard room size in an apartment is 20 m2, sometimes 25 m2. In this
article, we will talk about such rooms.
You can also calculate the power of air conditioners
using the rule – 1 kW equals 10 sq.m. Many
buyers use this rule. But you should consider that for more accurate calculations, it is necessary to use
the formula, which we will tell you about below.
Calculation formulas
As you now know, power is the main characteristic of any air conditioner. In this
article, we will show the calculation of air conditioners by the area of the room. This method suits
small rooms (up to 50 square meters).
To calculate the power, use the following formula:
Q = Q1 + Q2 + Q3
Q is the power we need to know;
Q1 is the thermal energy from the room;
Q2 is the thermal energy from the people in the room;
Q3 is the thermal energy from the electrical appliances in the room.
Q1
To calculate Q1, use this formula S*h*q/1000
S is the area of the room (in square meters);
h is the ceiling height (in meters);
q is a coefficient that must be selected depending on the room illumination (30
for dark rooms, 35 for rooms with average illumination, and 40 for sunny rooms).
Q2
An adult emits thermal energy:
Without physical activity – 0.1 kW;
When walking – 0.13 kW;
With physical activity – 0.2 kW.
Q3
A computer emits 0.3 kW of thermal energy and a TV – 0.2 kW. Most other
electrical appliances emit approximately 30% of the energy from their capacity.
Calculation example
For example, we will calculate the capacity of air conditioners for living rooms in an area.
Of 26 square meters. The standard ceiling height is 2.75 meters. Only one person in the room will use a computer and a small refrigerator.
The refrigerator’s maximum power consumption is 165 W. The room’s window is sunny.
First, we need to calculate the heat output of the walls and windows (Q1). Let’s use the formula we wrote earlier. Our calculation will look like this:
Q1 = 26 sq. m. * 2.75 m * 40 / 1000 = 2.86 kW.
Let’s also remember the thermal energy (Q2) emitted by someone living in the room. He will rest in the room without physical exertion. Therefore, we will choose a coefficient of 0.1 kW.
Do not forget to calculate how much thermal energy is emitted by household appliances in the
room. The computer emits 0.3 kW. And the refrigerator emits 0.05 kW, since 0.165
kW * 30% / 100% ≈ 0.05 kW.
We get that Q3 = 0.3 kW + 0.05 kW = 0.35 kW.
Now we can calculate the power:
Q = Q1 + Q2 + Q3 = 2.86 kW + 0.1 kW + 0.35 kW = 3.31 kW
So, we learned that to cool a room of 26 square meters with windows on the
sunny side, in which one person lives, using a computer and
A refrigerator and an air conditioner with a power of 3.31 kW are needed.
Most manufacturers have standardized power. A unit with a power of 3.5 kW will suit our requirements.
Please note
We did not consider several factors in the calculations, but they can affect the selection
of power. The calculations above are not ideal. They are more accurate than the selection based on the principle of 1 kW =
10 sq.m. But they are still not accurate enough to be considered a reference.
Let’s return to the factors influencing the choice of power. It is important to consider how much air can enter the room through an open window during ventilation. Our calculation method does not take into account open windows. This is because it is not recommended to open windows when the air conditioner is on.
If you decide to add data on open windows to the calculation, then simply increase Q1 by 20%
to compensate for the heat load. Also, add 15% to Q1 if the room is on the top floor and there is no cold attic above.
It is also important to take into account the glazing area. In typical houses, the windows are small, but in
new buildings, large double-glazed windows are often installed on the floor. The amount of
natural light entering depends on this.
Into the room. In the calculation, account windows are considered to be up to 2 square meters. For each additional square meter, you need to add 100 W.
Results
Now you know how to select air conditioners based on the area of the premises. You can independently calculate the power of air conditioners based on the area of the premises, but we recommend entrusting this task to store specialists. They will be able to determine the optimal power of the air conditioner for use in any condition.
You calculate the power when operating in commercial and industrial facilities. In this article, we discussed only one of the calculation methods for household air conditioners.