Would you trade your AC for some extra MPG??

[NiHaoMike]

Originally Posted by Xringer

I don't ever recall seeing a failed AC in a car that still had much refrigerant left in it..


Anyways, my post isn't asking how to better run or repair a car AC..
It's about the desirability of dumping your AC for better MPG..

Pretend it was a regular dealer option at a used car lot.
They both cost about the same..

Pick one:

A. 10,000 BTU AC system installed w/25 MPG unlimited miles.
(Until you turn on the AC, then it's 23.5 MPG).

B. Plug-In Mild-Hybrid system installed w/30 to 38 MPG for trips less than 20 miles.
(After 20 miles, it's back to 25 MPG).

A wire could break, the compressor can burn out, a valve can stick, or an electronics board can fry just to name a few. All of which leave a broken A/C with all the charge still in it.

Even if you were removing the system altogether, you still need to recover the refrigerant in order to comply with EPA laws. It is illegal to intentionally "vent" refrigerant to the atmosphere, especially if it's an older A/C that uses R-22.

I think mine is still running. They say it's good to turn it one for a few miles at least once a month.

Not that myth again! The capacitor depolarization problem that led to that myth is not an issue today.

That model is only rated for a max charge of 300g.... I drive a midsize classed car (2000 Jetta), which is spec'd for a charge of 700g + 50g

Danfoss doesn't make a 750g model, but it does make a 800g max model... Which, under max load, draws 660W @24VDC

The compressor does not determine the maximum charge in the system. The charge specification is if the compressor casing is used as the only accumulator. It can easily be a lot higher if there is a separate accumulator.

[SVOboy]

I ditched my a/c system. If I could get an electric retrofit I would do it though.

[jamesqf]

I would, since I hardly ever use it anyway. Maybe a couple of times a year, when I have to cross the San Joaquin valley in the afternoon. Unless it's hellishly hot, I much prefer having the windows open and adapting my body to the ambient temperature to sitting in a climate-controlled box - which usually means a stream of frigid air blowing on my chest - and then shocking my system with an abrupt change when I get out.

[Clev]

Originally Posted by jamesqf

I would, since I hardly ever use it anyway. Maybe a couple of times a year, when I have to cross the San Joaquin valley in the afternoon. Unless it's hellishly hot, I much prefer having the windows open and adapting my body to the ambient temperature to sitting in a climate-controlled box - which usually means a stream of frigid air blowing on my chest - and then shocking my system with an abrupt change when I get out.

I drove for a couple of summers in a dark maroon exterior/black interior Nissan 240SX with no A/C in 105 degree Modesto heat; I'll take the A/C. :-)

As far as gains from removing the system: if you leave it off, you're only driving the outside of the clutch (which probably doesn't have any more drag than the A/C bypass pulley), so a little extra weight notwithstanding, I'd rather have the option of the cooling/dehumidifying that A/C provides.

[Xringer]

"Even if you were removing the system altogether, you still need to recover the refrigerant in order to comply with EPA laws. It is illegal to intentionally "vent" refrigerant to the atmosphere, especially if it's an older A/C that uses R-22."

I guess if someones head was buried in the sand for the last 20 years,
he wouldn't know about the EPA laws, Ozone layer & skin cancer & etc..




I think mine is still running. They say it's good to turn it one for a few miles at least once a month.
Not that myth again! The capacitor depolarization problem that led to that myth is not an issue today."


I seen start-up caps go bad on AC electric motors (120V 60hz) But never heard of one being in the AC of a car... Learn something new everyday..

I had heard you had to turn you car AC once in a while in the winter to keep the lube moving around. (For some reason). Who knew it was a lie??

[99metro]

I pulled my AC right after I bought it. Still haven't removed the condenser yet though. I bought it for fuel economy, not for all the bells and whistles.

[NiHaoMike]

Originally Posted by Xringer

I seen start-up caps go bad on AC electric motors (120V 60hz) But never heard of one being in the AC of a car... Learn something new everyday..

I had heard you had to turn you car AC once in a while in the winter to keep the lube moving around. (For some reason). Who knew it was a lie??

The electronic modules used with DC compressors have capacitors as well. It's not easy to see with the Danfoss compressors as the modules are enclosed, but here's a compressor with an open board where the capacitors are visible:

That is actually a compressor used to cool the processor chips in some of the fastest servers and workstations.

Startup is actually the most stressful on a compressor. The bearings are operating without lubrication until the oil pump operates. Some compressors like the Copeland Scroll actually use the hydraulic pressure of the lubricant to enable compression so as to reduce stress during startup and reduce inrush current.

[bennelson]

Adding a motor to the belt in your engine compartment is pretty much a description of GM's "Mild" hybrid BAS (belt-alternator-starter) technology.

That's the system used on the Chevy Malibu Hybrid. It only gets about 2 mpg better than the regular Malibu.

I think a clever home-builder might be able to do something similar, but with a bigger MPG gain.

Perhaps a system like this on a manual transmission vehicle with a good kill switch might work.

Coast to stop signs. Pull away with your Air-conditioning replacement, and turn on the gas once you get going!

I would think this would be more efficient on a car smaller than a Malibu.
I believe the GM "mild-hybrid" system is 36V. A 3 or 4 battery system should work fine on a small car. The Etek motor I have in my motorcycle would work great!

[jamesqf]

Originally Posted by Clev

I drove for a couple of summers in a dark maroon exterior/black interior Nissan 240SX with no A/C in 105 degree Modesto heat; I'll take the A/C. :-)

Well, sure, and if I lived in Modesto, I probably would too :-)

But if I did live in Modesto, I sure wouldn't have a dark-colored car. Even in Reno, I have light colors - silver Insight 'cause they didn't make white, and a white Toyota PU. Along the same lines, I'm almost always able to plan my trips so I head across the hot part of the valley in the morning, or at night. That way I beat the heat, and the worst of the traffic.

[wagonman76]

I almost never use my AC anyway. The Celeb is the only vehicle I have where the factory AC even works. I usually just roll down the window about 1/4. The summer is way too short here, I would rather appreciate the fresh air when I can without freezing.