After a winter 2017-2018 long, gray and cold, spring is here and there!
The sunny days are coming back, the temperatures are rising and with them, the risks of heat wave or heat wave.
If it is rather easy to fight against the cold, protecting yourself from the heat is more difficult and the use of air conditioning techniques is almost compulsory in the event of extreme heat. This is especially valid for the most fragile people, such as babies or people of the third age ... We still remember tens of thousands of premature deaths during the heat wave in France in 3! The use of air conditioners could probably have saved many lives!
What is an air conditioner? How does it work ?
An air conditioner works like a refrigerator…. except it's an open-air refrigerator (and you're in it)! It is a thermodynamic refrigeration circuit which uses the latent heat of evaporation and condensation to pump the calories, that is to say heat, from one place to another.
A cold circuit consists of:
- of an evaporator, it is the cold part (this is called the cold source: the calories are "pumped" there to the refrigerant circuit fluid, so the temperature of the evaporator drops)
- a compressor, it is the engine of the refrigerator which will pressurize and move the gas
- a condenser, it is the hot part, the grid behind the refrigerator (this is called the hot source, the calories are "pumped" there from the fluid and this will cool and condense the gas and increase the temperature of the 'evaporator)
- a regulator which allows the gas to regain volume after evaporation without increasing pressure
An air conditioner is an "open" refrigerator with two fans: one to bring in cold air, the other to extract hot air! It's a bit like leaving the door of your fridge open and putting a fan in front of it… Except that, in this case, as the calories are evacuated in the same room, the overall result will be negative : the room will eventually heat up. For air conditioning to work, the calories must therefore be evacuated to another environment, that is to say, most often, outside!
For this to work, the hot source, i.e. the black radiator behind the refrigerator, would have to be located in another room, ideally outside in winter and in the cellar in summer. Obviously, in the case of domestic refrigerators, this does not exist, but professional cold rooms all have their hot source (condenser) outside, just like stationary air conditioners.
Reversible air conditioning and dehumidification
When the circuit can be reversed, then we speak of a reversible air conditioner which makes it possible to make hot instead of cold in the "useful" room. More commonly, this is called a heat pump. A refrigerator is therefore a heat pump, like all air conditioners that use a compressor. Indeed, there are other cold circuit technologies such as, for example, cold by adsorption or absorption.
Finally, many heat pumps or air conditioners also have a built-in dehumidification function. A dehumidifier is therefore also a suitable refrigeration circuit so that the cold part (evaporator) is constantly below the pink point (condensation point of the ambient air)
In summary, an air conditioner can therefore:
- get cold,
- make hot (if reversible)
- dehumidify the air in a room (if the model allows it).
Now that the theory part is done, let's move on to practice. How to choose the right mobile or fixed air conditioner?
Mobile or fixed air conditioners? Comparative advantages and disadvantages of both types of air conditioning.
An air conditioner is chosen according to its cooling capacity in Watts. Each manufacturer gives indications in relation to the volume and / or the recommended surface. Count around 150 Watts per m² to get good cooling power. Quick comparison between fixed air conditioners (wall mounted with an external battery) and mobile air conditioners (on wheels)
A mobile air conditioner will therefore bring you freshness wherever you want and at a lower cost. However, its main drawback is having an evacuation of the hot air via a flexible pipe (supplied) which can be unattractive.
Its main advantage is its high mobility and low price, both purchase and installation!
To go further and if you have questions about an installation: visit our website forum on thermal comfort
2 comments on “Health: heat wave or heat wave, think of auxiliary mobile air conditioners!”
What is the point of advertising for mobile climates?
It's good for the planet? Good for my wallet? No…
Que Chooser has tested a few. You have to count 500 € to have something correct. The models at 200 €… Hmmm and leave a door open for a mobile air conditioning, a good example of mess!
Really not sure that we can reconcile the economy and the ecology for future generations with stuff like that… and refrigerant gases with a high greenhouse gas potential, are we talking about it?
Completely agree, these mobile clims are a heresy and when I see that most are in energy classes To see A +… I am talking about monoblocs with a single drain pipe which represent the majority of the offer: indeed as much to leave his fridge open, because even if we evacuate hot air (or cold for a reversible), this is necessarily replaced by air, admittedly a little less hot which re-enters through the half-open window, or by the ventilation of the house. It's stupid, the energy balance of the device in this global context must be closer to C than to A and I wonder if it is out of stupidity or complacency to keep the economy running that the authorities are letting this believe.
If you opt for a mobile air conditioning, therefore choose a system with an outdoor unit (mobile split) or a monobloc system with 2 pipes to the outside (the manufacturers should provide it as an option as long as it would hardly change the device design), so you will move calories and not air masses and we will approach the overall efficiency of a real air conditioner.