engine question... chilled air intake?

[foxfitnessrepair]

using either a chemical thats stays colder than ambient air (if such a thing readily available) or coiled copper tubing flowing compressed refridgerant all the way around the intake for increased hp? Just throwing this idea out been dreaming it up for a while now. Other sensors would need to be calibrated for this change of course but is this even possible? Turbos would love it if so.

 

[KENAT]

Um, isn't that essentially what an inter cooler does in-between turbo stages etc.?

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[rb1957]

yes, chilling the intake air will increase the output of the engine, it'll increase the thermal efficiency of the engine ...

but you'll be adding more energy chilling the air than you'll recover from the improved output. that's why it doesn't make sense to do this to a car, but it could make sense to do to a stationary engine (getting the chilling power from the electrical grid).

 

[foxfitnessrepair]

ah makes sense (rb1957) due to the loss of about 10-15 hp with compressor running anyways?
And KENAT ya more or less but it only cools the air with passing air not "chilled" air. they have intercooler sprays either nitrous or another fluid I forget now but there only temporary boost of colder air. Essentially I am thinking of a worse idea of just using nitrous due to its cooling properties. OOPS!

 

[dgallup]

Power is roughly proportional to the amount of air you can pump through an engine so anything that packs a denser charge into the cylinder will increase power. You see all kinds of schemes from spraying alcohol to dry ice to cool the charge. Mostly for very short competitions like drag racing so you don't have to haul a lot of weight around.

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[ScottyUK]

This is fairly common on gas turbines in power generation applications. The chiller plant consumes less power than the improvement in engine output, so there is an economic case for chilling in these large stationary applications. It may be a little awkward to fit an industrial gas turbine to your car but if you do succeed then please post the results on YouTube.

 

[rb1957]

"The chiller plant consumes less power than the improvement in engine output" ... that sounds like perpetual motion ... i suspect you mean that the energy cost of chilling is economically acceptable (less than the value of the increased ouput).

 

[zdas04]

I've done a few projects in places that habitually have low humidity (deserts, high elevations, etc.) where we put an evaporative cooler on the air intake. This can add over 100 hp on a 1000 hp application on a 100°F day for almost no power input (not perpetual motion, latent heat of vaporization). Even in winter if you have adequate freeze protection it can get you a buzz (but it is a lot more complex).

If you have to add a traditional refrigeration cycle it doesn't ever pay off. If you can tie on to "wasted" cooling capacity in a chilled water cycle then the economics can work, but they are generally marginal.

I've had a couple of scoping projects where we were going to dump engine heat (including a turbo after cooler) into an evaporation pond. The thermodynamics were impressive, the economics were very positive, but the culture of Oil & Gas wouldn't allow either project to move forward ("by God we've always cooled compressors with fin-fan coolers and that is the way it is going to be done on this project, the evaporation ponds are someone else's problem").

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

 

[geesamand]

Not only is intercooling effective, but liquid injection (methanol/water or pure water) is excellent for keeping both charge temperatures down by evaporative cooling as well as permitting higher combustion chamber pressures free of detonation and preignition effects.

 

[foxfitnessrepair]

is the liquid injection a "spray" onto the intercooler? my first idea was more for non turbo applications. Like an intake on steroids, but I can see that spraying intercoolers must heavily drop the temp of incomming air. I know generally a non "sprayed" intercooler only adds about %1 efficiency but adding an out side cooling liquid must dramatically increase that (especially nitrous) but seems expensive and weight of tanks must be a factor in drag/circuit applications when every ounce counts. A little off topic but does nyone have experience with the edlebrock street legal turbos? Thinking about grabbing a civic for a fun little car to play with, good brand and it looks like a quality kit but im in CA so im always scared of smog! (sorry for the ramble)

 

[KENAT]

Reason I brought up inter cooler was because I was thinking given the higher temperature/bigger temperature difference after the first turbo stage would make cooling there more efficient.

However, it's been a while since I looked at much thermo stuff in any detail

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[rmw]

Do a search on the site with a few of the key words in this thread. The topic is actually being discussed quite intellegently in some other currently running threads.

Alternatively google "TAS" and follow the links.

rwm

PS: Scotty, I take it that David isn't very familiar with the refrigeration plants of your former world.

rb1957, it isn't perpetual motion. The chiller plant is a parasitic load. It is just that the net gain in output is higher than the parasitic load.