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How does an air conditioner work?

March 6, 2013 by Shaun Day

Air conditioner Remote control

Air conditioner Remote control


From Wikipedia,

Air conditioning is the process of altering the properties of air (primarily temperature and humidity) to more favourable conditions. More generally, air conditioning can refer to any form of technological cooling, heating, ventilation, or disinfection that modifies the condition of air.

However, Air Conditioning involves a lot more than this. Everything you need to know about an air conditioner is explained and detailed below in order to give you a clear understanding.

Mono-Splits, Multi-Splits… what are they?

For the home, we can distinguish two main categories of efficient air conditioners that operate in ‘Cooling and heating ‘ mode: the Mono-splits and the Multi–split system, in simple terms, it means simple or multiple.

Each of these categories is slightly different in some way: the way to install them, the specifications such as: cooling& Heating power, electric consummation, sonority, energy classification…
Most current air conditioner units can be controlled by a remote and get the specification: ‘dehumidifying’.


Air conditioner Midea

Air conditioner – Midea Luna


The cold air created by an air conditioner including the specification ‘Dehumidifying’ helps dry the air which improves the comfort in high humid rooms or areas. Thanks to a filtration system, most sophisticated air conditioners are able to purify the air.

This process is called ionisation

The Single-Splits air conditioners (or Mono-splits) are fixed: This means that these type of air conditioner can only provide air in one room, within a restricted surface. Regarding the Multi-splits, in opposition to the Mono-splits, they are manufactured in order to be operational in lots of rooms or even a whole house. Both (Mono-splits and Multi-splits) have their advantages and inconveniences, therefore most of them include a reversible mode.

Due to our partnership with Powrmatic (Accredited specialist of air conditioning), we are going to provide you important information if you are looking for purchasing a specific product.


How does Air Conditioning work?

Before anything else, let’s explain how air conditioning works.

An air conditioner is a thermodynamic machine that creates cold air on 1 end and hot air on the other end. Its principle is similar to the refrigerator. In broad outline, it’s composed of two exchangers (one evaporator and one condenser) associated to a compressor which is pumping. The whole system works in a waterproof closed circuit, where a refrigerant fluid flows that can become alternatively liquid or gaseous.

This plan may help you to understand:

Air conditioning schema

Principle of an Air Conditioner 


As seen above via this broad outline, the ambient warm air is collected and then refreshed in the evaporator as soon as it touches the liquid that has just became gaseous. The fluid (now gaseous) progresses until the compressor, where this gas is compressed by being warmed up by the compressor (via High pressure).
The warm compressed gas is then sent to the condenser.

The Cooling Mode Cycle:

The role of the condenser is to change the high pressure gas from hot gas vapour to cool it down to high pressure liquid, after it has been created by the compressor.
The condenser the high pressure liquid continues on its journey towards the indoor part called the evaporator, now at the beginning of the evaporator you will find the famous Expansion Valve.

In some cases it is called the (EXV) Electronic Expansion Valve.
These type can be found in the DC inverter units, this device controls the flow of liquid creating a spray action that reduces the pressure of the liquid and creating a cooling effect into the evaporator.

While the indoor fan of the indoor unit is circulating the warm air of the room through the evaporator, it is picking up the cold air from the evaporator and leaving the heat absorbs from the room on the evaporator coil, which this is called ‘heat exchanging’.
This alternation of different steps/phases is indefinitely repeated until reaching the required temperature. The thermal exchanges speed-up via a ventilation system electronically regulated.


The Heating Mode Cycle:

The heating mode cycle of an air conditioner it is all the same as the cooling mode cycle but a reverse cycle valve changes the direction of the high pressure gas coming from the compressor taking it to the indoor unit.
With this heat and high pressure passing through the indoor unit the heat is released in the room creating a nice warm temperature and this time the hot gas changes state to liquid state while it being exchanged with the cold air passing through the indoor unit.

So in simple English it is like: getting the outdoor unit and the indoor unit and swapping them over the indoor you take outside and the outdoor bringing it inside to release the heat in the room.
The advantage of this reverse cycle valve is you are heating the room via a heat pump method, which is the only most economical way of using 1 Kw of Energy consumption and producing 4 Kw of Heat, at the most efficient and faster way possible.


3 types of Air-Conditioning examples:


                                               The Mobile unit                                           

Mobile Monobloc 

  The Window unit

Wall mounted Monobloc

The Multi or Single splits units



Difference of these 3 types of units:
  • The Mobile unit: is an air conditioner which is designed to cool the area you are in as a temporally basis and it is portable so you can place it as close as possible to your heat source. Obviously being as a temporally basis unit, this is the least economical of cooling or heating your area.
  • The Window unit: is an air conditioner which has to be installed half outside and half inside. This type of unit is designed to cool a room which has no outdoor unit space and you do not have other choices of place to install but unfortunately this unit can be noisy and less comfortable due to the cooling and heating effect of these types comes with a price of consumption and a noisy room.
  • The Multi or Single splits unit:  is an air conditioner which everybody has been waiting for… These units comes in a lot of indoor choices and designs to choose from at your likes, the sound noise again are all whisper silent, so you are enjoying the cooling and heating effect at no convenience of any other noise.  You can have either 1 indoor unit to 1 outdoor unit or 2 or more indoor units to 1 large outdoor unit. The choice is in your hands but this type of air-conditioning is the most efficient and economical way to have your comfort temperature at a push of a button, with instantaneous effect.  Regarding your home, solutions can be different according to the type of property (flat or house) and the situation of the people living in it (renter or owner). In apartments, the installation possibilities depend of the rules established by the council or the city, but more importantly, it depends on the sound insulation.


In any house, all options can be conceivable. However, the local regulations can impose restricted conditions (E.g.: Your area is classified as ‘natural heritage’).

For this reason, it’s very important to investigate the law in order to get legal authorisation(s) or even ask a qualified and accredited fitter. can recommend an accredited fitter near your home when purchasing with us.


ECA                  Euro air                   ISO 9001               ICOM Energy Association


Air conditioners with ‘DC inverter’

In order to explain it technically, the procedure explained how the refrigerant cycle through the system to create cooling and heating, the DC Inverter type has a an inverter driven compressor, this is the latest technology in Air-Conditioning systems which is all electronically controlled that reduces and increase the power of the compressor according to its demand, so it will only consume energy according to its demand needed.

These are all considered to be on the A++ energy ratings, which with the New CO2 European legislation all units have to meet this category.

This is an example of a Single Split system:
Cooling mode - Single Split (Air Conditioning)

Cooling mode – Single Split


Heating Mode - Single Split (Air Conditioning)

Heating Mode – Single Split


Economic heating…

Despite good thermal comfort at any time of the year, the inverter air conditioning will save you some energy expenses thanks to a ‘coefficient of performance’ or COP (sometimes ‘CP’) from 2 to 3.


To summarise:

When the ‘heat pump’ uses 1000 Watts in action, the output reaches 4000 Watts: in fact, that is equivalent to 1 kW/hour paid for 4 kW/hour consumed!

(It’s not that easy though).
The outside temperature can play a big part on the performance of the air conditioning.




When the temperature is near 0° C, most of the time with classic air conditioners, the output is weaker but the electric consummation is proportionally increasing.

That’s why, often, the inverter splits are the best solution.

Enjoyed it? Check out our latest posts!

Air Conditioning, Heaters

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