I understand why new furnaces are more efficient, but why AC?

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I think I understand why new furnaces are more efficient, but why AC?
I finally read an explanation about the exhaust air being cooler, as low as 90 degrees F from gas furnaces, and more heat extracted from the fire to heat the house, in new furnaces. I presume new oil furnaces are more efficient the same way.
But why are new AC's more efficient. There is no cold air going up the chimney with an old AC. I presume that if the refrigerant doesn't lose all its coldth, warm up to room temperature, in the AC evaporator inside the main air duct, when it returns to the condensor, it's that much easier to condense because it is colder, and less heat has to be radiated out from the condensor fins. So iiuc there is no loss there, at least if that pipe is insulated.
So why are the new ACs more efficient?
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wrote:

Not a single clue, here.
By next January R22 (?) is illegal?
I'm being bombarded with these "energy credit" savings ads for a new HVAC unit.
My unit is 12 years old...
It might work in may case?
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They'll sell you anything. It doesn't mean you need it. But I have no idea.
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That is not exactly true On Jan 1 they can't make new R-22 systems unless they are filled with recycled R-22. They can still make new R-22 for repair of that system tho. It really sounds like there is a lot of room to cheat if someone wanted to. I am still not convinced there ever was anything to the freon scare. China and India have been going full blast, manufacturing R12 and R22 systems for their people since "Montreal" in the late 90s.. Without the punishing taxes, I doubt they recycle any of it. Even with all the recycling, virtually all freon gets vented anyway from leaks. That is why they will still be able to make it until 2010 for "repairs".
In spite of all of this new freon in the world. the ozone hole that everyone had their panties in a wad over, shrunk.
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The first thing about newer high efficiency a/c is the coil size-- both condenser and evaporator. A new 2 ton unit is physically larger than most 5 ton units of yesteryear. Scroll compressors (that most but not all use) are somewhat more efficient than recips. The condenser coils themselves, as well the whole condenser fan assembly are designed-- with computer aid, not available years ago-- to get the optimum airflow with much lower horsepower fan motors than old units, as are the evaporators also.. All the motors-- condenser fan, blower, and compressor, have been "tweaked' to maximum efficiency. Most all higher SEER units use expansion valves instead of fixed orifice or capillay tube refrigerant flow control. A few 13 SEER units use flowrator (fixed orifice) , but pretty much all above 13 are TXV. Most all 16 + SEER units are two stage, some even having two compressors. Just as with fuel mileage on cars, the manufacurers have gotten all the easy gains in efficiency they are going to get. Barring some breakthrough invention, future efficiency gains will be small and costly. HTH Larry
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On Fri, 6 Nov 2009 00:12:08 -0600, snipped-for-privacy@webtv.net (Lp1331 1p1331) wrote:

Thanks and thanks to all of you.
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On Nov 6, 1:31am, snipped-for-privacy@aol.com wrote:

. Because the better organized and more responsible countries of the world took measures to reduce the release of the older style refrigerants into the atmosphere and/or legislated the use of less polluting (although possibly less effective?) ones for new production.
It does kinda prove two things, a) Humans activity can/does affect the planets environment. b) Measures can be taken to change activities that pollute. Somewhat encouraging actually if our politicians would stop squabbling and pointing at each other and actually act instead of worrying where their next campaign contribution will come from!
In Canada, for example, those in the refrigeration industry and maintenance business have operated under some very strict measures. But have visited gulf countries in the Middle East where, along with a booming economy based almost entirely on the production of oil and gas, there were few if any refrigeration controls. R22 could be bought over the counter and anyone working on auto and home AC units, considered almost essential on most vehicles and in all living units over there, would routinely just purge refrigerant into the atmosphere!
The situation is much the same as when the Europeans (particularly Britain) with industrial economies based on several hundred years of the use of coal finally decided that the health problems, disruption of travel and the corrosion and other deterioration caused by acid rain and smog were too high. Today, in the London UK area for example the use of coal has been just about banned for many past years.
In other words 'good-responsible' government. Just look at the mess irresponsible (weak) governemnt has done in the financial-banking industry!
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On Thu, 5 Nov 2009 23:08:02 -0800 (PST), terry

But this wasn't (just?) blamed on freon as I recall it. It was chloro-fluoro-carbons, which were just about eliminated from use years ago, weren't they, certainly in the high-consuming countries if not everywhere.

And Lake Erie or large parts of it had little or no life in it until steps were taken. I think there is also fishing around Manhattan Island now, that was not possible a few years ago.
I don't mean Mr. Fretwell, but it seems to be a matter of religious faith almost that the earth can't be ruined by people, and yet we've seen parts of it get ruined. I don't see why they are sure the whole earth couldn't be.
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Because it could mean they have to make some sort of personal sacrifice or endure some kind of hardship. Denial requires much less effort!
Eric Law
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Ozone holes aren't caused by "Freon in the world", they're caused by Freon (CFCs if you're trademark-averse) in the atmosphere.
China / India / whoever go berserk making new A/C's, the Freon stays inside them, everything's fine. *Until* it gets let out... by the A/C developing a leak or intentional release. Then the fun starts... 10, 15, 20 years from now.
Eric Law
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So Freon is a CFC. Oops. I checked and you're right. That makes my answer to Terry, whicch included an answer to gfretwell, pretty stupid.

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The chinese have been "going berserk" making the billion R12 refrigerators they promised in the 70s. Are you saying every one of them still has all the original refrigerant in them? That still ignores the fact that all freon gets vented eventually. As careful as you may be, the main reason most appliances get thrown away is the freon is gone. I also question how well we recycle. I know the fridge and the package AC unit I had the county haul away were vented in the street in front of my house ... after I heard all about the "special pickup" and how they had to do something special with the freon. They just grabbed the package unit with a claw truck and banged it in the bed until the freon blew out, then drove away. The guys cut the copper out of the fridge.
Yeah I know, I should have called the cops. They would have taken a report and that would be the end of it. In the end it would be my word against the county about whether gas really came out.
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wrote:

I'm not sure about that, although I'd agree it often escapes eventually. Especially in the case of car A/Cs, where leakage is just about guaranteed as the car ages.
On the other hand, when I was a kid I used to enjoy bringing window A/Cs home from the dump and seeing if I could make them work. Of those, I'd say maybe 1/3 had random electrical problems that were easily fixed, and almost all the remainder had seized compressors or fans (or both). Think I only ever saw one where the refrigerant had escaped.

That's really sad. I always suspected that happened some of the time, but I'd never heard a firsthand account before.
Eric Law
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Dear Eric:

The ozone hole is a natural, recurring event. The size of the hole, the date of start, the duration, and the minimum ozone value obtained... are a function of the contaminants in the "ozone layer". This includes chlorine- and bromine-containing compounds, as well as water vapor.

The fluorocarbons are next. We keep making inert compounds that can only leave our biosphere via the (nearly the) same energetic radiation that makes ozone. All because without the chlorine, bromine, or flourine there, they are too flammable for safety.
David A. Smith
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mm wrote: ...

Because they use better more efficient compressors, etc., to be able to produce more useful work from the same input energy.
That's what engineers are for... :)
--
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wrote:

Technically, I don't know. But window ACs, and even refrigerators, are a lot more efficient now, too. Could just be the insulation on the fridge, but just better engineering of blowers and fins and stuff can help, too. Just electric motors that don't surge but have electronics driving them, I think, maybe venting motor heat outside instead of inside, etc.
J.
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wrote:

Great answer.

Also good. :)

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wrote:

And thanks, all.
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mm wrote:

Some good answers. I don't know the technicality but when I got a new AC a few years ago, my summer electric bill was halved.
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On Fri, 06 Nov 2009 07:22:16 -0500, Frank

Thanks.
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