Always wondered. Why can you not use an AC to have a refrigerant cooled IC?
07-27-2005, 02:45 AM
#4
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Perpetual motion machines are illegal.
The violate the laws of thermodynamics. The power needed to drive the A/C compressor would exceed the power gained by cooling the intercooler that way.
07-27-2005, 04:22 AM
#6
Ok, then along those lines>>
the aerodynamic drag created by the intercooler sticking out in the wind somewhere at the front of the car should also exceed the power gained by cooling the intercooler that way, no?
I think what you mean is that the A/C compressor is not efficient enough to create any overall benefit.
How do you explain a supercharger -- it's driven off the motor but "makes power." I understand there is a law of conservation of energy, and these devices work within this law.
I think what you mean is that the A/C compressor is not efficient enough to create any overall benefit.
How do you explain a supercharger -- it's driven off the motor but "makes power." I understand there is a law of conservation of energy, and these devices work within this law.
07-27-2005, 04:43 AM
#7
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If you do it at seperate times it would work out
For example at WOT AC is shut off anyway.. so it would have to be cooled while not at WOT.. So really the power is being used at different times. Doesn't have to mean you are getting something from nothing.. Think of it like they hybrid gas/electric cars. They can run off gas or electric while accelerating. While driving normally they charge up the batteries a little if needed but yes thats going to take power to make the electrical energy. So they charge the batteries under breaking.
If you cooled say water of an air/water IC setup while just cruising or at idle. You would be able to get lower IC temps by lowering the waters temps during times when that extra power needed to run the AC is not needed anyway. Also remember if its in the summer the AC is running anyway for the most part (if you have it on obviously) so you can just use parts of the system already working.. What some people do is run copper tubing or similar around some of their AC lines (you know the ones that get all frosted up or condesation on them) They are already cold. Pump the water from the air/water IC through those copper lines and they will cool of on the AC piping.
This actually has been done before and I"ve heard of several different ways of pulling it off.. One would be what I just mentioned above.. Others have made it so the lines actually run through the resivour for the air/water setup. I've also heard of people putting the heat exchanger that would normally be in the front of the car in the hvac airbox.. All sorts of things can be done and have been tried..
If you cooled say water of an air/water IC setup while just cruising or at idle. You would be able to get lower IC temps by lowering the waters temps during times when that extra power needed to run the AC is not needed anyway. Also remember if its in the summer the AC is running anyway for the most part (if you have it on obviously) so you can just use parts of the system already working.. What some people do is run copper tubing or similar around some of their AC lines (you know the ones that get all frosted up or condesation on them) They are already cold. Pump the water from the air/water IC through those copper lines and they will cool of on the AC piping.
This actually has been done before and I"ve heard of several different ways of pulling it off.. One would be what I just mentioned above.. Others have made it so the lines actually run through the resivour for the air/water setup. I've also heard of people putting the heat exchanger that would normally be in the front of the car in the hvac airbox.. All sorts of things can be done and have been tried..
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07-27-2005, 05:27 AM
#8
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the supercharger does make power>>>
but until boost is "on"...it is a parasite, lots of drag. So if not tuned correctly it can effect performance when OFF boost...so while it is not a true driveability issue....it sap some of it's benefits....it is just small number.
07-27-2005, 06:04 AM
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Well, yes...
I was being "flip."
I might have been more specific and said that it's very inefficient compared with a standard intercooler. Where is this extra drag you refer to? If the intercooler isn't up front creating drag, the other parts of the car are. It's not like it's mounted on the roof. Intercoolers provide more peak power with little or no loss of efficiency when that power is not needed. That would not be the case if cooling the intake with an a/c compressor. Not only is that cycle inefficient, but you still need a condenser in the airstream as part of the system, which is no less drag than a regular intercooler (which as I said, isn't much).
Superchargers effectively increase displacement when active. A supercharged (not turbo) engine is worthwhile for two reasons - most of the time the sc isn't doing much nor consuming much power (cruise). It provides near-immediate power when needed, so it's more efficient than an engine with equivalent displacement. If run only at full power, a naturally aspirated engine is more efficient. The other reason is weight savings, which may be more important than fuel efficiency in some applications, such as airplanes.
Of course, turbos work of of heat which would otherwise go out the exhaust, so they're "free."
I might have been more specific and said that it's very inefficient compared with a standard intercooler. Where is this extra drag you refer to? If the intercooler isn't up front creating drag, the other parts of the car are. It's not like it's mounted on the roof. Intercoolers provide more peak power with little or no loss of efficiency when that power is not needed. That would not be the case if cooling the intake with an a/c compressor. Not only is that cycle inefficient, but you still need a condenser in the airstream as part of the system, which is no less drag than a regular intercooler (which as I said, isn't much).
Superchargers effectively increase displacement when active. A supercharged (not turbo) engine is worthwhile for two reasons - most of the time the sc isn't doing much nor consuming much power (cruise). It provides near-immediate power when needed, so it's more efficient than an engine with equivalent displacement. If run only at full power, a naturally aspirated engine is more efficient. The other reason is weight savings, which may be more important than fuel efficiency in some applications, such as airplanes.
Of course, turbos work of of heat which would otherwise go out the exhaust, so they're "free."
07-27-2005, 07:01 AM
#10
That would work for short bursts only.
The power consumed by the cooling system would exceed that gained by the cooler intake air. Now if you precooled a water reservoir during part throttle conditions and flowed it through a water cooled intercooler, it would give you a reserve for short bursts of full throttle till all the water got hot. Water spray on the intercooler will do the same thing however and its cheaper and lighter.
Anyone going to Barber this weekend?
Anyone going to Barber this weekend?