i'm doing just that now on my project! i'll let you know how it goes
ed

 

Great, Pinky! I'll be excited to hear your results!!!!

 

You Can Guess My Answer

http://en.wikipedia.org/wiki/Conservation_of_energy

Also nothing has 100% efficiency.

 

http://en.wikipedia.org/wiki/Conservation_of_energy

Also nothing has 100% efficiency.

Well, I posted what I posted because I understand the Laws of Thermodynamics including Conservation of Energy, Entropy etc. as well as Einstein's theorums. What I don't know is the hard numbers on how much energy is consumed by these small compressors compared to how much additional power may be realized through a denser fuel mixture. That's the question I was asking.

I don't know of a source of info or research into this subject as described. Therefore nothing to stab a pencil into.

 

Running a cooler could yield some gains, but you're going to be wasting a lot of crankshaft power for no real gain.
A bigger or simply better designed intercooler will give you the same net result (cooler air into the engine) while sucking no crankshaft power.

Some simple calcs. In metric of course.
3.9 litre engine running 2000rpm under 15psi boost and moderate intercooling, it's sucking around 115 litres of air every second.
That's 140g of air per second.

Lets say we have a cooler that can shift 3 kilowatts of heat. 3 kiloJoules every second.

work = mass*heatcapacity*change in temp.

Rearrange:
change in temp = work / (mass*heatcapacity).
change in temp = 3/(0.140*1.004)
change in temp = 21.5 degrees C.

Someone want to check that for me? it seems like a big change in temp and it's been a while since I've done thermodynamics homework.

 

Dougal

While the units aren't that farmiliar (I was one of the last classes to get 'schooled' with imperical WOO HOO, what a PITA). It doesn't seem unreasonable (just under 40*F temp drop).



Jimmie D

I would reccomend at least an air to air (or, plumbing the JWAC to cool water rather than coolant) as a 'primary' and only usng the 'refrigeration' under 'high loads' and plumbing that in after your primary cooler.

2 reasons

1 There isn't enough gain at low boost to justify the power draw of the compressor.

2 That compressor isn't going to last very long making it run all the time the engine is running (excepting the times the binary shuts it off of course).

Perhaps rig it to a hobbs pressure switch so it kicks in above a certain boost, and back off below it (IIRC somone sugested AC binary switches for a similar app, water inection, I think).

If you just want to try it, put your 'secondary cooler' in, and plumb it to a compressed gas cylinder (non flamable and non oxidising please) and when you want it 'on' open the valve. It won't last too long (till you run out of CO2, N2, whatever) and you have to make sure you vent that away from the air intake and you; but it would give you an idea (no the actual refrigeration system you describe would be unlikely to generate the 'instantaneaous' reduction in charge air temp as the system I describe, but would likely be more reliable and consistent).

Do be careful, mis handling compressed gas cylinders is dangereous.

 

with my build, i've got 3 turbos, a very large intercooler, and 2 stages of n2o.
i'm running a/c on my truck anyway, so i figured why not give it a try?
ed

 

with my build, i've got 3 turbos, a very large intercooler, and 2 stages of n2o.
i'm running a/c on my truck anyway, so i figured why not give it a try?
ed

One for the engine and one for the driver perhaps? (just funnin)

 

but ofcoarse! better living through chemistry!
ed:grinpimp:

 

This is related.
1. What would be the best air intake temp for the most efficient cumbustion?
2. What would be the best air intake temp for max power?

The measurement would be just before it compressed air went into the cylinder, say the intake manifold or right at the intake valve.


68F (20C)
32F (0C)
0F (-18C)
-20F (-29C)
-40F (-40C)
or ?

 

Thanks, guys! That suggestion of 'on demand' useage is real practical Nex.

I've never seen figures to give a clue as to a direct relationship between charge density/temp/horsepower gain. Theoretically you're cramming more air/fuel into intake and combustion chambers with a chilled intake but I wonder just how much?

Running more turbo would increase boost of course but hard to figure out how much of the power increase is from chilling and how much from the boost? I remember packing the aluminum intake on drag cars in dry ice before a run to boost power and it really worked. But the actual percentage power gain? Unknown!

On these Denso compressors remember that they run continuously for 9-10 months a year on a desert vehicle like in southern Arizona etc. for years & years. They can take it, no doubt.

I don't think they use much power but the only way to really know is to kick it on when on a dyno to actually see the paraysitic loss in real time or somehow measure the resistance effort to turn the shaft and calculate a measurement of horsepower loss.

Just seems to me that if intercooling/aftercooling by normal methods is such a big deal for power & performance then this has got to be a lot bigger deal for results?

.

 

I think you are giving the air conditioner too much credit. I would be very surprised if you saw much of a drop in intake temperature. Hope it works out for you, but if you compare the cooling effect of the AC on the really low airflow it takes to cool the cab, with what will be necessary to cool some 3 or 4 hundred CFM, it is quite a difference. I'm not trying to dissuade you, and it would be interesting to see the results, but I'm pretty skeptical. I've seen it mentioned from time to time in various circles, but never heard any results. I'd think that if it was worthwhile, there would be something somewhere about it. If someone did it and had positive results, they would most likely be bragging about it to anyone who would listen.

Good luck with it.

Doug

 

My thoughts are that the best way to chill that incoming air is either with a spiral coil of refrigerated copper tubing inside an air duct or tube so that air must pass over all of the coil surface. Second thought is a refrigerated radiator assembly that the intake air blows though on its way manifold.

Seems strange to me that an inter/aftercooler makes any difference in horsepower at all. Fuel doesn't come along til later so all it's doing is supposedly cramming more air in by shrinking the air column? Head scratching....

 

back when I was in tech school we dynoed a SS Camaro at operating temp, then built a PVC intake to pull air from the passenger compartment, let the car run until the interior was as cold as it was going to get, and re dynoed, saw about 15 ponies from the denser (cold) air charge. Granted the compressor turns off above a certain load, but the volume of air in the car was enough to allow us to see gains from the dyno run. Granted this was just a goofball experiment to prove to the class that the colder denser charge would make more horsepower.

I'm with Dougal however in more efficient intercooling would be a more effective answer, as its cooling the charge without removing engine power. You could always look into water/methanol injection, in conjunction with intercooling. I'm leaning to this myself for the compound setup. If you want to get really nutty, you could even spray CO2 onto your intercooler, or put it on nitrous.

 

Now that's some impressive numbers, xech! It's possible to get that intake mix at least twice as cold with direct refrigeration as the car's interior was I'm sure. Bears some looking into I think?

I agree with water/meth, may build my own system late next year. Cheap, works good, lasts a long time, hey, that's a winner!

 

The next stage of my calcs should have been.

What is the density increase?
In this case it's the temperature ratio.

If you're bringing in air at 20C (room temp) and cooling it down to 0C (freezing) then the density increase is the reciprocal of the temperature decrease.
In abosolute temp.
new density = 293K/273K
= 7.3% better.

At cruise I reckon the engine is producing maybe 40hp (30kw), so you're using about 7% of that power to get 7% extra charge density. Starting to sound like a waste of time.

 

I've thought about a freon-cooled intercooler for many years now... If power gains were only attributed to the increased density of the intake air, I might have to agree.... but if you are close to the thermal limit of the engine and you can lower the intake air temperature to a point where you can then safely add yet more fuel and boost without exceeding the thermal limit, then I think significant power gains might be realized by using a engine-driven "super-cooled" intercooler. Is there something wrong with that logic?

Using an analogy -- with an engine-driven centrifugal supercharger, conservation of energy would state that the blower would consume more power than is gained by addition of the blower -- I think just about any top-fuel team would be really disappointed to learn that they have wasted all that money all these years on expensive superchargers that couldn't possibly result in a net gain of power!

 

Hey Ed (Pinky),

I left you a pm. I might have some intercooler cores that might be suitable for your project!

Mark

 

you'll be better off block off the hoot coolant from the aftercooler and adding a cold water set up because if you still have the hot coolant in the system .

Or just add a air to air and do away with the water aftercooler.

Scott

 

I wonder if you could convert a water after cooler to a refrigerant evaporator? To me, you would want your refrigerant powered cooler to be right on top of the engine.

Also, about the 20C to 0C cooling, I think you are in the wrong temp range. I have not hard data, but am willing to bet that compressed charge air is in the 30C-100C range depending on ambient air temperature and boost pressure. I say this because if an air to air cooler makes a difference on a 110F Texas summer day, than the intake air has to be damn hot.

Also, if the air conditioner can pull that same 110F air in from outside and have it at 50-60F when it comes out the ait ducts, I think it has some cooling potential.

Now, will someone build it already so we can quit hypothesising and get some facts, already!

 

I was using the 20C range to indicate cooling air from ambient to below ambient. This temp range only exists at your air intake before the turbo.

There's no point using refrigeration to cool boosted air, as you, I and the others know that's over 100C for 15psi. There's no point using engine power to run a refrigeration system when a completely passive intercooler can be used to strip that heat down close to ambient without requiring whole kilowatts from the engine.

 

Would u be running some kind of radiator in the intake to run the refrigerent through to cool the air? I assume so. Wouldnt that create enough restriction to help kill alot of the gains? just wondering? I think if you really want to try it then go for it alot of people will say its not gonna work but you never know till u try it for yourself if anything you wll then know for yourself. After you figure it out let us know.

 

I had thought of a converted water cooler but maybe there's a better way. Now thinking of a much larger air duct with a continuous spiral [or 2] of copper tubing inside, that the charge air is forced over for the entire length. It would have to be sized so it's not a restriction and long enough that the air has a long exposure time.

I'd think a small diameter spiral of copper tubing down center and a larger spiral around interior wall of duct, all contained inside the ductwork? If it was all the same run of soft copper it could enter at one end and spiral down center to other end, then with the same tubing run, spiral it back in the opposite direction back to start again.

It might not need any supports inside if it wedged tightly against interior wall but possibly solder in a few flat-stock supports down length to prevent vibration and therefore hardening of the copper.

This could be wound around the right diameter tube for inner spiral then remove guide tubing and slide that spiral inside a larger diameter tube and wind back in the other direction, around outside of second guide tube, remove that guide tube and solder flat stock supports. Mark the actual duct tube you're using to catch the supports, drill, install tubing coils inside and fasten with screws.

Probably better if the duct is large than the diameter of largest coil so air passes over outside, too, within duct.

Not sure but I think copper is the preferred tubing for this coil instead of aluminum, can't remember which has better heat transfer?

With this setup the air is forced over cold copper tubing surface again and again for the full length of duct while tubing presents the least restriction to flow and longest heat transfer exposure time and the greatest possible surface area for cooling.

Of course one still needs an evaporator, thermal expansion valve and condenser for the refrigeration cycle.

.

 

The copper would have better heat transfer. The tubes you describe would be your evaporator (but yes, you would need all the other stuff you mention). The system (pump, lines, reciever drier, and evaporater) would all have to be sized to draw a lot of heat (your import econ-O-box pump, might not keep up, won't know for sure till you try it). It's not just the temp drop (degrees) it's the heat volume (it's what Dougal's pointing out, BTUs).

The heat exchanger in the JWAC is unlikely to handle the pressure involved in refrigeration.

 

Woops, I haven't worked in refrigeration & A/C for years: yes, we got your evaporator already!

You're right, have to spec out the system to see what's required. The Denso [I think that's the mfgr] compressor will do something but not sure if it's enough. Possibly their largest would do it. I hear they have terrific efficiency rates, very good units.

Thanks for the pics there Octamog! Pretty slick stuff. I'm thinking more backyard ingunearing on this if I do it. ******* at heart :rasta:

Sounds like Pinky49 is going to be our guinea pig, right Pinky? We'll see what happens. You're not that far away from me, a few hundred miles, so maybe I can actually eyeball it one day...

One more consideration: various refrigerants have different operating temperatures so a freezer type refrigerant is more desireable than A/C refrigerant. From a scalded memory, R601 or somesuch is for deep freeze and maybe there's stuff that's even better.

 

How it's done...

Usage with air conditioning systems
The Laminova intercooler can be combined with the air conditioning system for even better efficiency.

 

Laminova intercooler pics

Real-world pics of an intercooler using Laminova cores:

Posting on the build of the intercooler here.

 

Air/Water vs. Air/Air intercooler

This comes from someone who is way more knowledgeable about intercoolers than I, and has a bunch of data and experience to back it up.

AGAINST -

Complexity & Cost. You need a second radiator, water pump & preferably some form of pump speed control, 2 speeds will do the trick. They are much harder to size, this is why we have pumped hundreds of hours into data logging & creating a sizing spreadsheet programme. Under the same circumstances, drive in/out will be approx. 20 to 60% dearer.

It also became apparent after a couple of years testing that I had to down grade my initial cooling estimates of air/water intercooling, which is a disappointment, but necessary. I thought that I could design a system that at speed, would cool the charge air within 4ºc of a front mount - both systems being equally engineered. It appears 8 to 12 ºc is a real world figure. Please put this into perspective. A 'front mount' car - Skyline GTR, 180 - 200 Sx, Supra etc. will give results on a 25ºc day of 31 - 36ºc into the plennum. An air/water setup will give 42 - 48ºc under the same circumstances, but a 'non front mount' car - Skyline GTS-t, VL Commodore, Subaru - any car that doesn't have a front facing throttle body towards the radiator support - will give similar temps. due to heat soak in the long return pipe from under bonnet heat - approx 70 + ºc, even though the charge air in both air/air setups, exits the 'cooler at 31 - 36ºc.

FOR --

Now, the above paragraph is the only time a front mount will out perform an air/water if both are set up properly - at speed . Stop/start, drag racing, towing, 4 x 4 offroad etc. all gain from air/water. The charge air temps. into the engine are also much more stable with logging showing a spread of 35 to 40ºc around town & 35 to 50ºc laden in soft sand, 2nd gear low range, whereas, front mounts have logged 30 to 65ºc around town & 30 to 95ºc in sand. This is with turbo outlet temps of 140ºc as for a top mount, 38ºc c to 116ºc have been recorded ! When you have your foot right into it at slower speeds is when detonation is most likely to happen, air/air intercooling is performing at it's worst efficiency. A very big fan under a top mount will make a fair difference & to a lesser extent, behind a front mount, but none can get near the fact that water 'holds' heat 37 times better than air & a thin radiator at the front of a vehicle cools better than a thick intercooler (air flow), & also has much less effect on the volume of air flow too the engine radiator - very important with some vehicles - eg. 70 series Landcruisers.

from here: http://www.are.com.au/feat/techt/airwaterinter.htm

Also some interesting graphs from Kenne-Bell and a Laminova cored intercooler here: http://www.kennebell.net/techinfo/mazda/miata-dyno-results.pdf

(just to spur some dialogue)

 

A Laminova cored intercooler as shown wouldn't work in my vehicle. I'd never get it off the coffee table and if I did I'd take it in to snuggly up with at night! That's downright porn, boy, downright porn I tell ya! I'd have to buy 3, one for the coffee table, one for next to my pillow and one for the truck......

 

BTW: one heck of a build dialogue at that link, Octamog! Very interesting and one resourceful guy. I always envy clever machinists being more of a mechanic/fabricator myself.

Also thanks to everyone for some really great contributions to this thread and to Dougal for 'doing the math'

 

Octamog, that's a nice lookin' cooler you posted.

Here's a thread with some pictures of a somewhat different setup for them.

http://www.4btswaps.com/forum/showthread.php?p=48331&highlight=laminova#post48331