Frontal area rules?

maxSaleen · 06-12-2005, 07:28 AM

You guys remember a while back when the PA160 was first concieved by Cath? I remember somewhere in that multi hundread post thread Cather said something to the efffect that frontal area is the primary determining factor in a radiators ability to dissipate heat. If this is the case, which I think we can all agree upon, I propose this:

Radiator stacking. Much like fan stacking but with two radiators being placed on either side of a fan. Obviously the cores would have to be very shallow, have a low fin count, and be properly shouded. The benefit would be the increased frontal area of having two cores exposed to airflow.

Here is an experiment I'm considering: take my existing BIP and buy an additonal one. Run the two in series each with its own fan. Then cut out some of the fins (~1/2) and have the cores "stacked" onto one fan. This is just a crude description of the experiment. Before going ahead with something I would have to lay down something more in line with the scientific method. I feel the need to contribute somehting to this site at some point.

The benefit of having such a setup would be increased perfomrance while using only one fan and while using only one 12cm opening on a case.

What do you guys think?

HammerSandwich · 06-12-2005, 09:04 AM

Series airflow is never a good idea, whether with multiple rads or with thick cores. Same thing really.

jaydee · 06-12-2005, 10:14 AM

2 problems I see.

1) Warming second rad with first rads air.
2) Probably loose any gain by adding a second flow restriction.

If you have high caliber thermometers at your disposal it would be an interesting test though. You will need at least .01C resolution though.

Nugit · 06-12-2005, 10:47 AM

There is much benefit to having a greater frontal area. But it is mainly due to having a larger area to suck air in through, resulting in lower flow resistance i.e. a radiator more suited for low pressure silent fans.
With a radiator on each side of the fan you have the same frontal area, though what is increased is the depth giving a much greater air flow resistance. It may be worth a try with a really powerful fan..

Bloody_Sorcerer · 06-12-2005, 11:03 AM

what if the water went to the second rad first (first in the flow sequence, second in airflow order) and went from there to the front rad?

jaydee · 06-12-2005, 11:32 AM

Quote:

Originally Posted by Bloody_Sorcerer

what if the water went to the second rad first (first in the flow sequence, second in airflow order) and went from there to the front rad?

I can't see why it would matter. The water temp is always warmer than the air temp so either way the first rads air output will still be warmer.

|kbn| · 06-12-2005, 01:30 PM

Axial fans dont like pushing, but for a powerfull fan it works well pulling.

2x vahuall heatercores
172mm fan. Airflow doesnt change much with the second rad.
http://server5.uploadit.org/files/kbn2k3-rads.jpg

However I think a 120.3 setup would be quieter - fans over 120mm usually have very crappy bearings.
A 120.3 has probably as much if not more area than mine aswell.

maxSaleen · 06-12-2005, 02:03 PM

Would the frontal area not effectively be doubled? It would be like having two rads with two fans. One rad with one fan pushing, and another rad with another fan pulling. I agree that most fans are not very good at "pushing" air, but instead are better at pulling air. If one were to cut out most of the fins from a low depth core I don't see airflow restriction being an issue.

Bloody Sorcerer: That was exactly what I was thinking. The water would be cooled progressively.

Perhaps its time to buy a good thermometer...

maxSaleen · 06-12-2005, 02:05 PM

I should add that the modified BIP cores would be only experimental. A purpose made rad of my description would have even less depth; as little as .3 apiece. The fin count would be very low. In fact I might try the whole thing without fins and more tubes spaced closer together.

Cathar · 06-12-2005, 02:57 PM

The main reason why I said "frontal area rules" is for the lack of air restriction. A lot of frontal area means that the fan(s) have heaps of orifice area to move air through easily, meaning that a fan can run closer to its peak air-flow capacity.

What is being proposed here is the exact opposite, reduce the frontal surface area for the air to get through, and then worse, double up that restriction, and even worse again, feed the warm outlet air from the first radiator to the second radiator.

Honestly it really doesn't get any worse as a way to do it than what it being suggested in the opening post.

maxSaleen · 06-12-2005, 04:53 PM

Wow. I feel so smart. Cath has spoken. This thread has ended.

jaydee · 06-12-2005, 06:25 PM

Did you think the rest of us were full of it?

maxSaleen · 06-12-2005, 07:20 PM

Nah. I just take each for their area of expertise. Can't blame one for trying to think outside the box though, right?

jaydee · 06-12-2005, 08:21 PM

Quote:

Originally Posted by maxSaleen

Nah. I just take each for their area of expertise. Can't blame one for trying to think outside the box though, right?

It is how we learn I guess.

Marci · 06-16-2005, 10:35 AM

The majority of obvious ideas that you don't see in use aren't in use for good reasons.... basically...

maxSaleen · 06-16-2005, 09:40 PM

This is true, Marci, though some very obvious ideas have been overlooked for long periods of time. An example is with Saab. They recently released a version of their coupe designed to run on ethanol. Ethanol has an Octane rating of 110. This is too high for most engines to run on efficiently (don't ask me why, I'd say it screws up the compression ratio and the timings). Saab figured out that a higher engine pressure and modified timings would allow the engine to run very efficiently. Roughly a 10 percent increase in hp AND fuel economy. Just by adding a turbo and changing some timings. Considering that ethanol goes for $1.89 on average vs. $2.05 for 93 octane, I'd expect other manufacturers to follow suit.

Obvious concept, took the auto world a long time to realize it.

jaydee · 06-16-2005, 09:50 PM

Quote:

Originally Posted by maxSaleen

Obvious concept, took the auto world a long time to realize it.

Not really. Ethanol only became a better alternative in the last year as gas prices sustained at $1.90+. Pretty well known it runs smoother, cleaner and cooler. They have been using Ethenol in racing for years for those reasons. The main reason it has not been widely used in the average rig is it is hard to mass produce. If all cars today used Ethenol instead of gas it would cost $40 a gallon. Supply and demand is a bitch.

maxSaleen · 06-16-2005, 10:19 PM

Chicken and egg concept. You get enough demand, oil companies will figure out a way to get enough product on the table. The government would be willing to help out considering that 80% of the fuel's components would be "grown" domestically. This would be a huge boost to the economy. Think back to Henry Ford. Before him, cars were also very rare and expensive.

jaydee · 06-16-2005, 10:55 PM

Quote:

Originally Posted by maxSaleen

Chicken and egg concept. You get enough demand, oil companies will figure out a way to get enough product on the table. The government would be willing to help out considering that 80% of the fuel's components would be "grown" domestically. This would be a huge boost to the economy. Think back to Henry Ford. Before him, cars were also very rare and expensive.

There was 3 Billion gallons of Ethanol burned in US cars last year. They had a hard enough time keeping up with that as they set records. There is 375 million gallons of gas burned everyday in the USA alone in 2004. So there was as much gas burned in 4.5 days as there was all year for ethonal....

Anyway your argument for your other argument stated car manufactures took a long time to realize the benefits of ethanol which is completely incorrect. Henry Ford used it in 1907 in his First Model T. They have been using it in Brazil for a long time. By 2007 they are requiring 100% of new cars to be able to run on it (in Brazil). They are also using it in all other types of engines.

Ethanol is an excellent fuel that only suffers from lack of ability to mass produce it. It most likely will replace gas sometime in the future but no time soon. Probably not in our life time.

EDIT: Forgot to mention I build gas stations for a living.

maxSaleen · 06-16-2005, 11:52 PM

I'm aware of the fact that ethanol has been in use for a very long time. I'm just saying that it hasn't been used properly. A fuel with such a high octane rating is going to need a lot of oxygen for proper combustion. Normally aspirated engines are not capable of this. Any engine with a pressure boost will increase the amount of air (and therefore oxygen) and thus be more efficient with higher octane fuels. I'm not saying that the auto industry overlooked ethanol. I'm just saying they overlooked its proper use.

I'm hoping to see hydrogen or some other energy currency take the place of traditional gasoline. I feel that it is having an enormously detrimental effect on our economy. I'd imagine you'd second this, JD.

Just think if we could eliminate our dependance on foreign oil.... the imagination runs wild.

aaronspink · 06-17-2005, 04:34 AM

Quote:

Originally Posted by jaydee

There was 3 Billion gallons of Ethanol burned in US cars last year. They had a hard enough time keeping up with that as they set records. There is 375 million gallons of gas burned everyday in the USA alone in 2004. So there was as much gas burned in 4.5 days as there was all year for ethonal....

A large portio of that Ethanol was burned in Cali, and actually cost us more than the equivelent amount of Gas would of.

Quote:

Ethanol is an excellent fuel that only suffers from lack of ability to mass produce it. It most likely will replace gas sometime in the future but no time soon. Probably not in our life time.

The main problem with ethonal is efficiency of production where the amount of land and resources required to build the biomass to produce the ethanol approaches the enegery generated by it. As a bi-product fuel source its great, but as a primary fuel source it does leave a lot to be desired.

Tempus · 06-17-2005, 08:54 AM

Quote:

Originally Posted by jaydee

There was 3 Billion gallons of Ethanol burned in US cars last year. They had a hard enough time keeping up with that as they set records. There is 375 million gallons of gas burned everyday in the USA alone in 2004. So there was as much gas burned in 4.5 days as there was all year for ethonal....

I keep trying the math here and I get stuck.

killernoodle · 06-17-2005, 09:35 AM

Quote:

Originally Posted by Tempus

I keep trying the math here and I get stuck.

Yeah, someone must have misplaced a decimal or forgot to carry the 1 or something

jaydee · 06-17-2005, 10:23 AM

Quote:

Originally Posted by Tempus

I keep trying the math here and I get stuck.

Haha, opps.... Not sure what I ****ed up there, long day at work yesterday.

Errr, so that makes what? 8 days instead?

HammerSandwich · 06-17-2005, 10:29 AM

Quote:

Originally Posted by maxSaleen

A fuel with such a high octane rating is going to need a lot of oxygen for proper combustion. Normally aspirated engines are not capable of this.

Incorrect on both counts. Octane rates a fuel's willingness to burn and has little to do with the stoichiometric ratio for complete combustion. For a given mass of fuel, ethanol requires much less oxygen than gasoline. Converting a gas engine to alcohol requires that the carb jets or fuel injectors be approximately doubled in capacity, which allows proper fueling for the same amount of air. Without making this change, the engine would run terribly lean - if it would run - even without a turbo.

Alcohols actually have less energy density than gasoline, but using twice as much fuel allows greater power to be made. Doesn't help cruising range with an X-gallon tank, though.

Check out this table.

Alcohol will allow more aggressive tuning than gasoline. This can come from more compression, boost, and/or timing. It's also somewhat more tolerant of lean mixtures, though this is more of a convenience for the tuner than a performance advantage per se.

06-12-2005, 07:28 AM	#1
maxSaleen Cooling Savant Join Date: Dec 2004 Location: Orlando, Florida Posts: 383	Frontal area rules? You guys remember a while back when the PA160 was first concieved by Cath? I remember somewhere in that multi hundread post thread Cather said something to the efffect that frontal area is the primary determining factor in a radiators ability to dissipate heat. If this is the case, which I think we can all agree upon, I propose this: Radiator stacking. Much like fan stacking but with two radiators being placed on either side of a fan. Obviously the cores would have to be very shallow, have a low fin count, and be properly shouded. The benefit would be the increased frontal area of having two cores exposed to airflow. Here is an experiment I'm considering: take my existing BIP and buy an additonal one. Run the two in series each with its own fan. Then cut out some of the fins (~1/2) and have the cores "stacked" onto one fan. This is just a crude description of the experiment. Before going ahead with something I would have to lay down something more in line with the scientific method. I feel the need to contribute somehting to this site at some point. The benefit of having such a setup would be increased perfomrance while using only one fan and while using only one 12cm opening on a case. What do you guys think?

06-12-2005, 09:04 AM	#2
HammerSandwich Cooling Savant Join Date: Oct 2003 Location: 15143 Posts: 358	Series airflow is never a good idea, whether with multiple rads or with thick cores. Same thing really. __________________ www.procooling.com: It's true we are often a bunch of assholes

06-12-2005, 01:30 PM	#7
\|kbn\| Cooling Savant Join Date: Feb 2004 Location: W. Sussex, UK Posts: 329	Axial fans dont like pushing, but for a powerfull fan it works well pulling. 2x vahuall heatercores 172mm fan. Airflow doesnt change much with the second rad. http://server5.uploadit.org/files/kbn2k3-rads.jpg However I think a 120.3 setup would be quieter - fans over 120mm usually have very crappy bearings. A 120.3 has probably as much if not more area than mine aswell. __________________ Waterblocks

06-16-2005, 10:35 AM	#15
Marci Cooling Savant Join Date: May 2003 Location: Wakefield, West Yorkshire, UK Posts: 486	The majority of obvious ideas that you don't see in use aren't in use for good reasons.... basically... __________________ www.minimotosidecars.org / www.thermochill.com / www.themusiccollective.co.uk

06-12-2005, 10:14 AM	#3
jaydee Put up or Shut Up Join Date: Dec 2001 Location: Spokane WA Posts: 6,506	2 problems I see. 1) Warming second rad with first rads air. 2) Probably loose any gain by adding a second flow restriction. If you have high caliber thermometers at your disposal it would be an interesting test though. You will need at least .01C resolution though.

06-12-2005, 10:47 AM	#4
Nugit Cooling Neophyte Join Date: Jun 2003 Location: Aalborg, Denmark Posts: 85	There is much benefit to having a greater frontal area. But it is mainly due to having a larger area to suck air in through, resulting in lower flow resistance i.e. a radiator more suited for low pressure silent fans. With a radiator on each side of the fan you have the same frontal area, though what is increased is the depth giving a much greater air flow resistance. It may be worth a try with a really powerful fan..

06-12-2005, 11:03 AM	#5
Bloody_Sorcerer Cooling Neophyte Join Date: Apr 2005 Location: Near frozenCPU Posts: 55	what if the water went to the second rad first (first in the flow sequence, second in airflow order) and went from there to the front rad?

06-12-2005, 02:03 PM	#8
maxSaleen Cooling Savant Join Date: Dec 2004 Location: Orlando, Florida Posts: 383	Would the frontal area not effectively be doubled? It would be like having two rads with two fans. One rad with one fan pushing, and another rad with another fan pulling. I agree that most fans are not very good at "pushing" air, but instead are better at pulling air. If one were to cut out most of the fins from a low depth core I don't see airflow restriction being an issue. Bloody Sorcerer: That was exactly what I was thinking. The water would be cooled progressively. Perhaps its time to buy a good thermometer...

06-12-2005, 02:05 PM	#9
maxSaleen Cooling Savant Join Date: Dec 2004 Location: Orlando, Florida Posts: 383	I should add that the modified BIP cores would be only experimental. A purpose made rad of my description would have even less depth; as little as .3 apiece. The fin count would be very low. In fact I might try the whole thing without fins and more tubes spaced closer together.

06-12-2005, 02:57 PM	#10
Cathar Thermophile Join Date: Sep 2002 Location: Melbourne, Australia Posts: 2,538	The main reason why I said "frontal area rules" is for the lack of air restriction. A lot of frontal area means that the fan(s) have heaps of orifice area to move air through easily, meaning that a fan can run closer to its peak air-flow capacity. What is being proposed here is the exact opposite, reduce the frontal surface area for the air to get through, and then worse, double up that restriction, and even worse again, feed the warm outlet air from the first radiator to the second radiator. Honestly it really doesn't get any worse as a way to do it than what it being suggested in the opening post.

06-12-2005, 04:53 PM	#11
maxSaleen Cooling Savant Join Date: Dec 2004 Location: Orlando, Florida Posts: 383	Wow. I feel so smart. Cath has spoken. This thread has ended.

06-12-2005, 06:25 PM	#12
jaydee Put up or Shut Up Join Date: Dec 2001 Location: Spokane WA Posts: 6,506	Did you think the rest of us were full of it?

06-12-2005, 07:20 PM	#13
maxSaleen Cooling Savant Join Date: Dec 2004 Location: Orlando, Florida Posts: 383	Nah. I just take each for their area of expertise. Can't blame one for trying to think outside the box though, right?

06-16-2005, 09:40 PM	#16
maxSaleen Cooling Savant Join Date: Dec 2004 Location: Orlando, Florida Posts: 383	This is true, Marci, though some very obvious ideas have been overlooked for long periods of time. An example is with Saab. They recently released a version of their coupe designed to run on ethanol. Ethanol has an Octane rating of 110. This is too high for most engines to run on efficiently (don't ask me why, I'd say it screws up the compression ratio and the timings). Saab figured out that a higher engine pressure and modified timings would allow the engine to run very efficiently. Roughly a 10 percent increase in hp AND fuel economy. Just by adding a turbo and changing some timings. Considering that ethanol goes for $1.89 on average vs. $2.05 for 93 octane, I'd expect other manufacturers to follow suit. Obvious concept, took the auto world a long time to realize it.

06-16-2005, 10:19 PM	#18
maxSaleen Cooling Savant Join Date: Dec 2004 Location: Orlando, Florida Posts: 383	Chicken and egg concept. You get enough demand, oil companies will figure out a way to get enough product on the table. The government would be willing to help out considering that 80% of the fuel's components would be "grown" domestically. This would be a huge boost to the economy. Think back to Henry Ford. Before him, cars were also very rare and expensive.

06-16-2005, 11:52 PM	#20
maxSaleen Cooling Savant Join Date: Dec 2004 Location: Orlando, Florida Posts: 383	I'm aware of the fact that ethanol has been in use for a very long time. I'm just saying that it hasn't been used properly. A fuel with such a high octane rating is going to need a lot of oxygen for proper combustion. Normally aspirated engines are not capable of this. Any engine with a pressure boost will increase the amount of air (and therefore oxygen) and thus be more efficient with higher octane fuels. I'm not saying that the auto industry overlooked ethanol. I'm just saying they overlooked its proper use. I'm hoping to see hydrogen or some other energy currency take the place of traditional gasoline. I feel that it is having an enormously detrimental effect on our economy. I'd imagine you'd second this, JD. Just think if we could eliminate our dependance on foreign oil.... the imagination runs wild.

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