Air Conditioned Oil Cooler, anyone seen one? Options

[maf914]

QUOTE (bd1308 @ Aug 12 2005, 04:21 AM)

why don't people use this at home??? freon, when compressed, gets quite warm.... object is to shed heat.....run some cold water through it.... and you have an increased effeciency in your cooling abilities with freon and wamer water for the hot water heater...

This is becoming more common as people use hydronic cooling for the AC condenser in their homes. A common arrangement is to circulate water through buried tubing which allows you to achieve a 60 degree (typical ground temperature) water source heat sink. This is more efficient than 100 degree air in the summer or 32 degree air in the winter (in heat pump mode). Besides the increased efficiency you also replace the noisy condenser fan with a quiet water pump. The downside is the first cost of burying a bunch of plastic tubing in your yard. I hope to do a systen like this in the future.

[bd1308]

i was going with another approach....

but geo-thermal climate control is a neat thing....

very expensive now, but soon will come down.

supply and demand..

[SpecialK]

DJsRepS is correct on the pressure increase from the added load being a Baaaad thing, automotive A/C's weren't designed for that. Plus, the added heat would definitely effect the operation of the high/low pressure switches in the system.

Neat concept tho.....Hey, how about mounting a residential window unit in your front trunk, and using a power inverter to run it!! (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[SpecialK]

QUOTE (bd1308 @ Aug 12 2005, 10:31 AM)

i was going with another approach.... but geo-thermal climate control is a neat thing.... very expensive now, but soon will come down. supply and demand..

I assisted in the installation of a couple of geo-thermal heat pumps. Wasn't so much the cost of the equipment, but the labor involved that jacked the price up.

[Demick]

Mark

This sounds kind of like someone opening their freezer door to try and cool off their house - the end result is that the opposite happens.

The only real way to get rid of heat on a car is to eventually dump it out to the air. You have oil that you need to dump some heat out of. But rather than going straight to the air, you are suggesting transferring that heat to an A/C system. When you do that, the AC system now needs to get rid of that same amount of heat. Only the AC system takes work to do that. Where does that work come from? The engine. So the engine now needs to produce more power to run the AC system. Doing this work generates even more heat that will need to be gotten rid of as well. Where is all this heat going to go? Eventually, into the airstream as well - so now you've got to size your AC condensor (which is really just a radiator) to get rid of all that heat.

Here are some example numbers.
Say you want to dump 20,000 watts of heat from the oil.
So you transfer it from the oil to the freon.
The Freon now has an extra 20KW of heat to get rid of.
Due to efficiency of an AC system, it will take about 8KW of power to get rid of the 20KW of heat.
So the engine now needs to make an additional 8KW of power.
But the engine will create about 8KW more heat in generating this extra power (24KW of fuel --> 8KW goes to power, 8KW of heat goes out tailpipe, 8KW of heat goes to cooling system)
So now your oil has an extra 8KW of heat in it because you tried to us an AC system to get rid of 20KW of heat.

Anyway, you see my reasoning here. Bottom line is, you need to get the heat out to the air, and a radiator of some sort is the only real way to do that. So either way, you've got to have enough volume of air flowing through a large enough radiator - whether that radiator is an oil-to-air, water-to-air, or freon-to-air style, or any combination of the above. But going straight from oil-to-air will by far be the most efficient.

The laws of thermodymanics are at work here. The only part of it that you have a say in is the efficiency of the system. There's no magical way to get rid of the heat - it has to go somewhere.

Demick

[messix]

ford lighting trucks used a airconditioning powered intercooler between the supercharger and the intake that only was active during full throttle.

just some thing of related but useless info

[zymurgist]

My W126 (Mercedes-Benz 420SEL) has a fuel cooler.

It also routes engine coolant through the windshield washer reservoir so the washer fluid doesn't freeze.

Those German engineers think of everything.

[messix]

you mean over engineer everthing

[zymurgist]

QUOTE (messix @ Aug 12 2005, 01:10 PM)

you mean over engineer everthing

I can see why you might say that. However, having worked on the car extensively last year in a successful effort to turn it into my backup daily driver/weekend cruiser, I had nothing but admiration for the Mercedes engineers' attention to detail. Rack and pinion system to tension V-belts, flare fittings where the AT lines connect to the radiator (no hose clamps there!)... the way the car was put together shows that they thought about how it was to be serviced (rather than merely how it was to be assembled at the factory), and to me that indicates that they intended for the vehicle to be in service for many, many years.

And speaking of vehicles that have been in service for many years, the newest 914's are approaching 30 years old.

[bd1308]

with the exception of the battery rot, the 914 IMHO was done the very same way.


some things they couldn't help--ie the pot metal door handles and the $$$$$$$ hand grenade...

[bondo]

I agree with what Demick said, but there could be some advantages. There is inefficiency in extra steps of heat transfer, but the if the AC system raises the delta-T enough, it could work. Say the oil is at 250 degrees, and the freon is at 30 degrees.. the transfer of heat to the freon is going to be very effective, because of the huge temp difference. Now if the compressed freon goes to like 300 degrees to shed the heat, it can do it with less radiating space than an oil cooler at 250 degrees. I don't know if that's the way it would happen, but if it did, it might be enough to make up for the added load and related added heat. I don't know anything about the raised system pressures, but that can't be a good thing.

[zymurgist]

And also with the exception of the non-galvanized sheet metal that the body was made from? Well, personally I wouldn't blame Porsche for that. I mean, look at other unibody cars of the same vintage and see how they have fared for rust.

Datsun 240Z? Rust.
British roadsters? Rust.
Porsche 911? You guessed it, rust.

Corvettes have held up better over the years because they use a body-on-frame construction. If the frame rusts, you can replace it (although most people just part out the car at that point).

[Mueller]

QUOTE (bd1308 @ Aug 12 2005, 11:28 AM)

and the $$$$$$$ hand grenade...

huh??

what part of the car would that be??

Mark,

Since the motor is a nice big /6, you could possibly use "bleed" air from the fan to help cool the oil-cooler.

On my 3.6 in the 911, there is a hose installed in between the fan housing and the distributor to help get rid of the ozone gas that attacked the rubber belt.

Now you have "free" cooling (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[bd1308]

no imagination......



mps (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif)

[Mueller]

QUOTE (bd1308 @ Aug 12 2005, 11:44 AM)

no imagination...... mps (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif)

considering there are still good MPS's being used 30 years after being first manufactured, that is pretty darn good engineering in my book....

[SpecialK]

Okay, how about using a small secondary evaporator coil (downstream of the pass. comp. evap coil) to cool the air blowing across a standard air-to-air oil cooler. No huge load on the compressor, and would only pre-cool the air (all important Delta T) when the outside temps are high enough to justify running the A/C. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

The ducting wouldn't have to be all that elaborate, and a blower wouldn't really even be need if the inlet was in the air stream.

[bd1308]

yeah but who makes beryllium diaphragms nowadays?

nobody.

imagine ten years down the road when the steel ones are all that are left.......

[bd1308]

yeah but who makes beryllium diaphragms nowadays?

nobody.

imagine ten years down the road when the steel ones are all that are left.......

i agree it was a good engineering idea.....

just weren't made to last....

look at how many there were, compared to how many there are now.

[Jake Raby]

All I know is that an oil cooler with a block of dry ice strapped to it with a zip tie works very well....

Don't ask how or when I tried this!!!!

[Mueller]

QUOTE (bd1308 @ Aug 12 2005, 11:54 AM)

yeah but who makes beryllium diaphragms nowadays? nobody. imagine ten years down the road when the steel ones are all that are left.......

how many you want??

You can have them made all day long.............the problem is no-one wants to put up the money to do the R&D and have the first batch of them made.....it's been looked into, figure about $5,000 would be needed in order to have the first run of parts made.......

there is no shortage of beryllium-copper.........