Portable air conditioner ...

[m1979]

Maybe it will be a weird question... but...

A single hose portable air conditioners are inefficient, as they take the air from the room and remove it using a hose, some air is cooled down and returned to the room...

Ok... so why does it work like this? Why the hot air is removed at all??? It would be easier to take the air, cool it down and that's it, nothing should be removed from the room :)

Lets consider dual hose units... why do they take the air from the outside at all (sometimes it is hotter than the air inside of a room)? Why doesn't they work using air from the room only?

[monkey spanners]

All an air con system does is move heat from somewhere it is not wanted (e.g. your house) and put it somewhere it doesn't matter (e.g. outside)

If a portable can't reject its heat outside it isn't going to do any usefull cooling.

[m1979]

Thx

So it is not possible to work in a closed circuit? Why? :)

To make it easier:
1. Twin hose unit takes the air from the outside (that is hot) and cools it down. It also takes the hot air from the room and removes it
2. Why cannot it be achieved without any hoses, just cooling the air

[james10]

the heat has to be rejected somewhere on a split Air conditioner the heat is rejected outside, it is carried in the refrigerant and rejected outside via the condenser, the hose on a portable should be fed outside the area to be cooled to reject the heat as the condenser is mounted adjacent to the evaporator, in short if you need to cool you need to remove heat and to do that you need somewhere to put it as heat is a difficult thing to store

[monkey spanners]

I am not familiar with the two hose versions but i would expect they would take in outside air through one hose pass it through the condenser (the bit the heat comes out of) and then return the now warmed air (warmed with the heat removed from the room) to the out side, there would be a air intake grill in the unit that takes in warm air from the room passes it through the evaporator (the bit that removes the heat that comes out of the condenser) and then returns the now cooled air to the room through another grill.

Why can't it be achieved whithout any hoses, just cooling the air (for mobile units)? Same reason you can't keep eating without taking a poop, if stuff is going in, stuff has to come out somewhere too.

Jon :)

[m1979]

Ok so why cannot be the air taken from the room, cooled down inside of the unit and just returned? There is an option like this e.g. in a car - it can use the air from inside only (closed circuit) :)

Maybe I am missing a point? Let me give u another example. Let's say I have a basket full of water, hot water. I can:
1. use an empty cup, take some water from this basket, put it in a fridge for 10minutes and then back to the basket. If I repeat this process 100 times, the water in the basket will be cold :) - that is what I understand by a closed circuit
2. use an empty cup, take some water and get rid of it. Take some hot water from another source, cool it down and put it back in the basket - that is how I understand split/twin hose air conditioning

So why option number 1 is NOT possible?

[monkey spanners]

Ok so why cannot be the air taken from the room, cooled down inside of the unit and just returned? There is an option like this e.g. in a car - it can use the air from inside only (closed circuit) :)

Maybe I am missing a point? Let me give u another example. Let's say I have a basket full of water, hot water. I can:
1. use an empty cup, take some water from this basket, put it in a fridge for 10minutes and then back to the basket. If I repeat this process 100 times, the water in the basket will be cold :) - that is what I understand by a closed circuit
2. use an empty cup, take some water and get rid of it. Take some hot water from another source, cool it down and put it back in the basket - that is how I understand split/twin hose air conditioning

So why option number 1 is NOT possible?

1 is possible, its how it works! It cools the same air in the room not air from outside. But this is the point i am failing to explain, For some air to get cold it is necessary for some other air to get warm because you can't destroy energy only move it about, this is the reasons for the hoses, to get rid of the heat through.

In your water example imagine the water is heat, and you remove the water/heat from the container with a cup but don't empty the cup very soon the level will cease to drop, same with cooling it needs to go somewhere somehow either with hoses, an external condenser or a proper ac system with an indoor and an outdoor unit.

http://www.air-conditioning-and-refrigeration-guide.com/refrigeration-cycle.html

[Brian_UK]

I think that you are missing the point. The air taken from the room, cooled, and returned to the room. If it was taken from outside, hotter, then you would need a machine that was about four times as big.

The hose is taking the hot air generated by the cooling process and discharging outside the cooled space, some indoor air is removed in the process.

[m1979]

Thx guys. And sorry for a lame question but I did not find the answer to it anywhere :)