hacker-pschorr

I was a bit confused by that one, stared at it a bit trying to wrap my head around what they were trying to accomplish. Reading your post, my confusion is justified

So, in the image you posted, the air enters the three black areas and exits three similar opens on the bottom side, correct?


How about this setup - currently the IC's on the fastest production car in the world. The second fastest car (Bugatti Veyron) also uses air / water IC's, haven't seen a good photo of them yet.

Vlocity

OK....always willing to learn.
I plumbed Tank to Pump to Heat Exchanger to Intercooler then back to Tank.
My thoughts were that the coolant would be at it's lowest temperature after leaving the Heat Exchanger and that pulling from the tank would reduce any potential spike in temperature as much as possible.

Ken

blau928

Erik,

Yes, the air enters in the black colored slots, which is curved around the shape of the Laminova cores, to keep the air as close to the fins as possible. (tthe blue pieces touch some of the fins just barely on the inside curved portion). This is the way the cores get to be efficient, as the air has to go there. In addition, the design of the fins, being 0.3mm apart creates a Laminar flow around the surface of the core..

My comment about bends is based on physics, air or any gas, does not like to turn when being flowed. The bends create a restriction in flow. Restriction in flow creates a pressure drop at each bend, and gets worse if the bends are not optimized.

There is give and take here based on amount of airflow..

You need to expand on fastest production car in the world, my knowledge is limited to the amount of manufacturers, as there are so many specialist ones like Noble, Gumpert, 9ff, Ruf, Ascari, and a host of others I forgot already. In addition, fastest could mean top speed, flying kilometer/mile, or other things..

Maybe the pic you posted is from a Gumpert Apollo..? (Motor looks like an Audi motor which is used in those cars...) I may have a pic of a Veyron setup, if I find it I will post it.. The thing has 4 turbos, and I think 12 radiators. The plumbing is a nightmare to say the least...

On the pic you posted, the layout is better than the one before, in that the bend radii are optimal for the tubing size. However, the mini tunnel ram with the Laminova cores is still my preference on a V motor IF THERE IS SPACE for it, as you will have a straight shot at the port once the charge leaves the intercooler.

Cheers,

hacker-pschorr

Sorry, meant to put this link in there:

Shelby SSC Ultimate Aero (no relation or any association to the cranky old Texan who is behind the Cobra).

http://news.cnet.com/8301-13640_3-9794823-43.html

blau928

Ken,

If set up the way you had it, the thermal storage of the water used as coolant is not maximized.

The way I described, The coolant is at ambient in the tank, and will pick up heat in the AWIC, then go to the radiator to have the heat rejected and back to the tank, and the cycle can start all over again, and that way your tank always has cool water. In addition, at higher speeds, the coolant can be a bit cooler than the ambient, due to the "wind chill" that you hear on your weather report. The key is to have reserves of coolant so you can keep your foot in it and keep the detonation gods at bay...!

Anyway, the other way, the water in the tank is heated to more than ambient by the hot water from the AWIC, and you lose the benefit of the same amount of water being able to cool a hotter charge....

In addition, the radiator for the system need not be that big, as in an opening 12" X 12" @ 60 mph, I think you will have about 3-4000 CFM of air blowing through it. That can cool a lot of hot water very quickly...

Mix in some Redline Water wetter surfactant to help the system... It's good stuff.. If you have Aluminum parts, use distilled water and the redline. Pure water is the best, unless you're running the car in very cold weather, then you can add glycol etc. (antifreeze).

Glad to help..,

Imo000

This is not possible. Wind Chill is just a term they use to describe how cold the air feels when wind is involved. The actual temperature of the air, regardless how fast the wind is blowing never chages. The air temperature remains the same when there is no wind or when a hurricane is blowing at 100mph.

Think abut it..... if you have a cup of water at 1 degree above freezing and the surrounding air is at the same temperature. No amount of wind will bring the air temperature bellow freezing to freez the water in the cup. Its basic Phisics.

Vlocity

Richard,

Can you point to any production based vehicles that are routed this way.

I'd also be curious to learn if Murph, DR or Carl run there setups in a similar fashion.

Ken

hacker-pschorr

Yes, the Murf928 IC is routed this way. At least they are supposed to be assuming everyone is following the directions.

blau928

Ken,

The Kleemann cars (Tuner in denmark) come initially to mind. The routing is what I was told by the engineers at Laminova. I can check and see what others I know of, but my guess is that this is the way all the OEM's are doing it if they use the Laminova cores. I can't say how others are doing it, but I am sure if you call Corky Bell in TX, he will also tell you the same thing. It is also written that way in his many books on the subject.

Cheers,

blau928

Imre, you are correct, I was mixing up the marine environment, where the radiator will lose it's heat to water that can be less than the ambient air.

My layman's explanation was not correct about air..

Let's try again to see if I can explain what I was trying to say while in a rush this morning..

The ambient air moving across the face of the radiator will have the ability to remove more heat at a faster rate than the water is carrying it is absorbing it from the intercooler when driving at speed provided the coolant resirvoir is properly sized. The ability of the thermal storage capacity of the coolant, and the heat rejection of the radiator, it is possible to have efficiency of the system to be 100%.

In a marine environment, it is possible to exceed 100% of the efficiency of the intercooler.

There, clear as mud... Hope that helps...

Imo000

I’m pretty sure this is still not possible. How can you achieve an efficiency higher than 100% of anything? 100% is 100%. Even in an ideal environment, thermal transfer has to be from one medium to another and just because of this, efficiency is lost. That’s just the way it is. You can get close to 100% but because energy has to be transferred, it can never be 100%. This is the main reason why, under the perfect circumstances, air-air intercoolers will always be more efficient than air-water (not including ice water or some other form off water chillers). Air-air has one less medium to transfer the energy through than air-water. Just like 4WD is less efficient (more hp loss through the drive train) than 2WD. At least that’s how I understand this. Am I wrong?

V2Rocket

one example i saw once was someone's comparison of the awic to modern engines.

air cooled engines worked for a while very well so long as air was routed properly, but watercooling allowed for higher power potential. and when you think of it, a water cooled engine relies on the same process as an awic.

hot gas in the chamber transfers heat to the (aluminum) block/head. the heat from the aluminum is then transferred (to a point, the system temperature is controlled via thermostat) to the water circulating, which then goes to the radiator to reject heat. i think that if you removed the thermostat from the system that the continuous flow of water would keep it pretty cool. however the engine should not be run without as it relies on the particular temperature control to run optimally. but an awic system that is free-flowing (no temp control) should stay very cool so long as the heat exchangers are sized properly compared to the IC core.

a popular argument against AWIC and for AAIC is that if there was a major benefit to AWIC over AAIC then all the endurance racers would be using them. however i think that the major reason they have shied away from AWIC is because of the weight of the system, a team that goes so far as to make a badge into a sticker to save weight (porsche) doesn't want to add a 5lb pump, 40lbs of water, 2x 4lb heat exchangers, the reservoir and all the lines to their otherwise stripped out car. i think their budgets are so high that they can afford a very efficient AAIC, and also generally are not bound by space constraints (big reason why AWIC is chosen on many cars) as they can engineer their chassis how they please.

tveltman

You can get over 100% VE in a NA engine with proper porting owing to resonance effects. Granted, this is somewhat of a constructed argument, but depending on how efficiency is measured, it may be possible. in an air-air cooler, the exchange fluid is always being replaced by fresh, so you never really raise the temperature of the exchange fluid (the ambient air), whereas your exchange fluid in the air-water will gradually heat up, dependent on your ability to shed the extra heat through a second exchanger. Furthermore, I think the difference in efficiency partly comes from the difference in heat capacities of water and air. While water has a higher volumetric heat capacity than air (about 4000 times, if wikipedia is to be believed, also measured in J/cm^3 K), water's cohesion and much higher viscosity hinder the thermal transfer from the solid phase (the aluminum fins in the intercooler) to the liquid phase. It is important to note that in all heat exchangers, barring one type which we don't see in the automotive world, there are TWO thermal transfer processes, one from the charge air to the fins of the heat exchanger, and one from the fins to the exchange medium (being water or air). In either case, the difference is the ability of the exchange fluid to interact with the exchanger fins, and as I mentioned, I suspect that the essentially infinite supply of cool air is what makes the AAIC so effective.

EDIT: a revised way of looking at the problem

I think it is worth noting that three orders of magnitude is an astounding difference, so even despite inefficiencies owing to increased viscosity, I would expect AWIC's to be more "efficient", in the sense that, in principle, they require about 1/4000 less exchange fluid. The rub, of course, comes with the fact that the AWIC working fluid is contained, and so has a finite amount. The mass of air flowing over a one square foot IC at 60 mph is 6.59 lb/s, or equivaliently, about 3 kg/s. If you look at the heat capacities of water and air (measured in J/g K), you see that the heat capacity of water (at 25C) is about 4.13 times greater than air, so to achieve the same effect as the AAIC, you would need a system consisting of approximately 1/4th of that mass of air, or .75 kg/s of water, or about 1.06 gal/s. Of course, you also need the ability to shed the heat from that water so that by the time it comes back around, it is cool again. 1 gal/s seems like an awfully powerful pump to me, although I certainly don't know much about such things. I think a tap in a typical bathtub produces about 15 gal/min, which is 0.25 gal/s, so imagine a pump capable of pushing out four times the water of a bathtub on full blast. That seems like a rather tall order for a compact system as would be needed on a vehicle, so I suspect that is the reason (as well as the issue of increased weight and complexity). Note that these numbers are all based on the very modest (and unrealistic speed) of 60 mph. The differences between AWIC and AAIC only grow as speed increases, meaning that you would need a doubly powerful pump to achieve the same effect at 120 mph. NB these numbers are rough, and don't take into account the issue of relative degrees of thermal transfer owing to viscosity and intermolecular forces.

blau928

Imre,

If you were to calculate the delta in temperature between 60 Degree water in the ocaen or lake, and 90 Degree air at ambient, you will be able to see that if the coolant is 60 degrees, and the heated compressed charge from the SC is 140 degrees, the energy transfer will go to the cooler water charge of 60 degrees, and be less than the ambient air of 90 degrees. The coolant's differential temperature is what makes this possibe along with the efficiency of the heat exchanger's efficiency.

Once the compressed air charge goes below the ambient air, you have achieved >100% efficiency... This is just plain physics as you mentioned in your earlier post.

I could post the thermodynamic equation, but it is a bit long...

Here's a simple version

Coolant 60Deg
Air charge 140 Deg
Ambient air 90 Deg

If the heat exchanger is 95% effiecient, then it will remove approximately 95% of the Delta T (I am not going to get into pressure differentials and gas volume etc, as that would be really long equation)

Delta T is actually the difference between 60 Deg coolant temp, and 140 Deg Charge air, or 80 Deg. 95% of 80 = 76 Deg, so 14 deg is added to the original 60 Deg of the coolant temp, = 74 Deg. the charge air temp is now 74 degrees, not 140, not 90... The difference between 90 and 74 is 16Deg.. So, 90/74 = 1.2162, or 121.62%

Again, I am not adjusting for density and pressure, as the equation is long..

The principle is the same with an ice box/chiller. All you are doing is creating a differential temperature. As a matter of fact, AWIC's are much more efficient than Air:Air if done properly. (Air to Air can only cool to ambient air temperature....)

The thermal reserve capacity of the coolant in an AWIC, and it's ability to have a delta in temperature less than that of air for the same amount of applied heat to the volume.

Think about it, it takes a lot more energy (heat) to move a cubic foot of water 1 degree than a cubic foot of air.

Hope that is clearer.. If not, a good explanation is in Corky Bell's book on supercharging, or turbocharging. It is explained better than in the physics books on thermodynamic equations.

Cheers,

Imo000

I understand what you mean but you are using certain terms incorrectly. The lake water intercooler will bring the intake temps bellow ambient but that doesn’t make it more than 100% efficient. If it would bring the intake temperature bellow the temperature of the lake water, ONLY than you can say it is more than 100% efficient. Same goes for air-air intercoolers too, then can never bring it to bellow ambient but can get it much closer than regular A-A units. None of them can be more than 100% efficient, it’s physically impossible. 100% is the maximum regardless what you are referring to. Maybe there are some examples in quantum physics where this is different but in the real world, 100% means “the absolute maximum”. Maybe in the boating world, they use over 100% efficiency, to explain certain instances but that doesn’t make it correct.

For example, if an engine is running at 100% efficiency, it converts absolutely all the energy from the fuel to rotational force. Now, if it’s running at 110%, that would mean it actually is starting to make more energy that it consumes and this is impossible.

Also, I truly beleive that an ideally sized air to air intercooler will alway be more efficient than an idealy sized water to air one. A-A has less boundries to cross and that's the only reason it will be more efficient.