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Theoretical air conditioning question

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Would it be possible to locate an air conditioning unit inside a house, say next to the furnace? Since air conditioning units basically remove heat from the air and dehumidify it, wouldn't it be more efficient to have such a unit cool air that's already been cooled, as is done in a car?

I don't know if actually locating the unit inside would be a good idea, but even having some sort of air exchange system whereby air from the house is drawn into the unit outside and is 'recooled' and sent back to the living area sounds doable to me.

Anything seems better than what central air conditioners do now, which is take air from the humid, hot outdoors, condition it, and pump it inside.

Can something be done about this? It'd be really really nice if A/C wasn't such a power draw like it is now. I'm not a physicist, electrical engineer, computer scientist, chemist or HVAC repairman, so please, refrain from calling me stupid.

🙂
 
my air recircs... the thing outside is only part of your system the part that cools the air is inside and normally draws air from the inside. I don't know of any homes with central air that draw air from the outside. the part outside takes the coolant and removes the heat and sends the coolant back inside to the condensor.
 
Yea air is sucked in through vents INSIDE the house, blown past evaporating coils, then blown back out 'registers'.

The idea of an A/C system is to move heat from the inside to the ouside. The 'out side' part is expelling the heat. Putting that inside would nullify the whole system.
 
Originally posted by: Fiveohhh
my air recircs... the thing outside is only part of your system the part that cools the air is inside and normally draws air from the inside. I don't know of any homes with central air that draw air from the outside. the part outside takes the coolant and removes the heat and sends the coolant back inside to the condensor.
Click to expand...
But every single air conditioning unit I've seen has a fan at the top of it (underneath the 'grate' which creates a downdraft, pulling air into the unit. What is the purpose of that fan?
 
Stupid. Sorry couldn't help it. A central air unit pulls air from within the house and pulls it over the coils to remove the heat. The cold air is the blown through the vents. The heated refrigerent goes to the outside unit wher the heat is blown off by the fan and compressed.
 
Originally posted by: jumpr
Originally posted by: Fiveohhh
my air recircs... the thing outside is only part of your system the part that cools the air is inside and normally draws air from the inside. I don't know of any homes with central air that draw air from the outside. the part outside takes the coolant and removes the heat and sends the coolant back inside to the condensor.
Click to expand...
But every single air conditioning unit I've seen has a fan at the top of it (underneath the 'grate' which creates a downdraft, pulling air into the unit. What is the purpose of that fan?
Click to expand...

To accelerate to cooling of the freon, so it can be pumped back into the house quicker.
 
Originally posted by: jumpr
Originally posted by: Fiveohhh
my air recircs... the thing outside is only part of your system the part that cools the air is inside and normally draws air from the inside. I don't know of any homes with central air that draw air from the outside. the part outside takes the coolant and removes the heat and sends the coolant back inside to the condensor.
Click to expand...
But every single air conditioning unit I've seen has a fan at the top of it (underneath the 'grate' which creates a downdraft, pulling air into the unit. What is the purpose of that fan?
Click to expand...

to increase the rate of heat exchange between the air and pipes
 
The only difference between what is going on in your car and the house is that when you set the car on recirc it closes the door to not draw in any outside air. If you stop and think about it your house is probably on permanent recirculate since all that happens is air is blown through the A frame where it is cooled before being blown out your registers. It then returns through 1 or 2 big intake vents in your house that go back through the furnace filter on the other side of the blower motor. All houses "breath" a bit which is where the outside air comes from, all the furnace system is doing is recirculating the air in your house.
 
Originally posted by: jumpr
Originally posted by: Fiveohhh
my air recircs... the thing outside is only part of your system the part that cools the air is inside and normally draws air from the inside. I don't know of any homes with central air that draw air from the outside. the part outside takes the coolant and removes the heat and sends the coolant back inside to the condensor.
Click to expand...
But every single air conditioning unit I've seen has a fan at the top of it (underneath the 'grate' which creates a downdraft, pulling air into the unit. What is the purpose of that fan?
Click to expand...
The laws of thermodynamics, thats why. The thing outside cools the freon, which in turn will cool the air inside of your house. The freon gets pumped from the outside cooler, to the central AC unit, which takes air sucked through the holes in your wall (you know those filters you have to change?) and cool and condition that air.
 
Originally posted by: theNEOone
no, the AC would actually work less efficiently if it were cooler air. have you taken physics?


=|
Click to expand...
Yes, but I didn't learn about thermodynamics.
 
First of all... One of the comments in here sounds a lot like it is referring to window A/C units in houses. Those do in fact operate much like car ones, and many have recirc/outside selection modes, just like a car.

Second of all... In a "real" central A/C system in a house, all the air is blown through insulated tubes in your attic or basement to the air vents in the ceiling or floor respectively. The air is sucked back in from one or two main returns. Thus your house is "always on recirculate" which is the most efficient cooling method for your house, despite what someone who didn't understand thermodynamics might say.

In recent years, houses have become airtight enough that some systems (although my understanding is that it is usually furnaces, not A/C setups) will in fact suck a percentage of air from the outside and inject it into the recirculation stream. That's because theoretically if your house is airtight, you could in fact use up all the oxygen and die, or at the very least your house would smell funkier every day. Again, it's a bigger issue way up north where you might find yourself inside without ever opening a door/window for days on end, whereas in more temperate climates you'd expect plenty of air exhange just from your normal coming and going, not to mention normal air leaks around doors and windows.
 
Anything seems better than what central air conditioners do now, which is take air from the humid, hot outdoors, condition it, and pump it inside.
Click to expand...

In case I wasn't clear, this statement is absolutely 100% incorrect.
 
Originally posted by: jumpr
Originally posted by: theNEOone
no, the AC would actually work less efficiently if it were cooler air. have you taken physics?


=|
Click to expand...
Yes, but I didn't learn about thermodynamics.
Click to expand...

It may be easier to cool hot air, but that is irrelevant. When you're talking about an AC system's efficiency you aren't talking about how much it cools air. You are talking about how much power it uses to get your house to a certain temperature.
 
Originally posted by: flot
Anything seems better than what central air conditioners do now, which is take air from the humid, hot outdoors, condition it, and pump it inside.
Click to expand...

In case I wasn't clear, this statement is absolutely 100% incorrect.
Click to expand...
Yeah, I sort of realized that by now. 🙂

I just thought the fan that drew air into an A/C unit was its ONLY source of air to be cooled. I was wrong. :Q
 
Originally posted by: jumpr
Originally posted by: Fiveohhh
my air recircs... the thing outside is only part of your system the part that cools the air is inside and normally draws air from the inside. I don't know of any homes with central air that draw air from the outside. the part outside takes the coolant and removes the heat and sends the coolant back inside to the condensor.
Click to expand...
But every single air conditioning unit I've seen has a fan at the top of it (underneath the 'grate' which creates a downdraft, pulling air into the unit. What is the purpose of that fan?
Click to expand...
It's blowing air across the condenser, so more heat can be exhanged.
In a car, the speed of the car pushes air across the condenser to do the same thing, and if the car is stopped, the cooling fan does it.
 
Okay, after re-reading I see you got that. That fan acts just like the fan in the front of your car - it's sole purpose is to suck air past the evaporator coils, so that the freon changes back from a gas to a liquid. Then it is pumped back inside, where it is allowed to evaporate - becoming a gas again. The cycle is repeated constantly.

Imagine it like a can of compressed air. The A/C unit outside is what stuffs the air back into the can, and the a/c unit inside is what lets it expand and come out and freeze your fingers off.
 
Originally posted by: flot
Okay, after re-reading I see you got that. That fan acts just like the fan in the front of your car - it's sole purpose is to suck air past the evaporator coils, so that the freon changes back from a gas to a liquid. Then it is pumped back inside, where it is allowed to evaporate - becoming a gas again. The cycle is repeated constantly.

Imagine it like a can of compressed air. The A/C unit outside is what stuffs the air back into the can, and the a/c unit inside is what lets it expand and come out and freeze your fingers off.
Click to expand...


Yup, the A/C unit outside does NOT bring air inside the house. It simply circulates freon in and out of the house.

On another note, many, if not most new houses in Western Canada are now being built with fresh air intakes on the furnace/ventialtion system in houses. Nothing else has changed, just a fresh outside air intake added in.

In my sisters new house, when you hit a switch near the thermostat, it turns the bathroom fan (which is of course moveing air straight outside) and the furnace system fan, which is pulling fresh outside air in. The manufacturer claims the entire house air is cycled every 1.5 hours. pretty sweet!
 
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