Condensor fans Push? Pull? Push/Pull?

[johann]

As the title say...


I know with watercooling It depends on fin density, for instance the bix is better in pull where the BIP is better in push because of less restriction.

Push/Pull you cannot say add 70cfm +70cfm. I find that one 90cfm fan pulls better than 2 x 70cfm fans in push/pull

In general condensors are quite dense, so what is best. Normally I go with single fan pulling but Im trying to get more silence so I want to try 2 x more silent fans in push/pull.

formula to work it out or comments?

[wdrzal]

always better to pull air

[ayrtonsenna]

pull is best in my experience especially if you have a good shroud on the condensor.

[johann]

what about push/pull?

[ayrtonsenna]

just pull. ie: one fan.

[LukeXE]

what about push/pull?

Actually, Johann you have right about push/pull, then you can use two more silent fans than one loud that is pulling. Maybe it will be that same good idea like one pulling fun and little bit silent.

I think...just check this out and tell us how it works in practice

[Carlz0r]

How will 4x120mm fans pushing do compared to pulling?

[LukeXE]

Notice, that if fans are pulling then they are cooling compressor too. If fans are pushing, that "pushed" air after condenser is moving slower than it will be pulled by condenser. Bigger Flow = better compressor cooling.

And other idea is that if fan are pulling then air is pulled by ALL the fins (of course of you have shroud), so it`s more efficient.

[Carlz0r]

Notice, that if fans are pulling then they are cooling compressor too. If fans are pushing, that "pushed" air after condenser is moving slower than it will be pulled by condenser. Bigger Flow = better compressor cooling.

The compressor already has its own cooling, I got a fan for it as well.

[LukeXE]

The compressor already has its own cooling, I got a fan for it as well.

I just have quessed that when I clicked "Submit Reply"

I edited my last post a little bit, I will copy that text:

"And other idea is that if fan are pulling then air is pulled by ALL the fins (of course of you have shroud), so it`s more efficient."

[Carlz0r]

I just have quessed that when I clicked "Submit Reply"

I edited my last post a little bit, I will copy that text:

"And other idea is that if fan are pulling then air is pulled by ALL the fins (of course of you have shroud), so it`s more efficient."

Ahh, I see. So if no shroud was used, there would be no difference really in efficiency?

[wdrzal]

one more time, ALWAYS pull air. Think of the physics of moving air....... why does it moove?

fan or blower simply changes the static pressure from one side to the other. since "mother nature" always likes a equilibrium all you need to do is lower the static pressure on one end of the case and air will rush in to fill it. the greater the pressure change the faster the air will move.



I used to work as apprentice mine engineer and we pulled air down a elevator shaft 360 feet then 4 miles to the face and 4 miles back out. you could never push air that far, but lower the static pressure at the exhaust and mother nature takes over........... we did use a 3000 hp 5 blade propeller fan. fan sounded like a airplane...it exhausted sideways and there wasn't a leave on the trees for 150 ft, except for the tree tops.

edit :the last sentence I posted in the other thread posted here too. don't know how that happened. when I hit save it took quit awhile to post.

[Carlz0r]

one more time, ALWAYS pull air. Think of the physics of moving air....... why does it moove?

fan or blower simply changes the static pressure from one side to the other. since "mother nature" always likes a equilibrium all you need to do is lower the static pressure on one end of the case and air will rush in to fill it. the greater the pressure change the faster the air will move.



I used to work as apprentice mine engineer and we pulled air down a elevator shaft 360 feet then 4 miles to the face and 4 miles back out. you could never push air that far, but lower the static pressure at the exhaust and mother nature takes over........... we did use a 3000 hp 5 blade propeller fan. fan sounded like a airplane...it exhausted sideways and there wasn't a leave on the trees for 150 ft, except for the tree tops.

edit :the last sentence I posted in the other thread posted here too. don't know how that happened. when I hit save it took quit awhile to post.

Yea, the forums have been acting strange lately.

[Unknown_road]

push/pull only causes interference and much noise.

push alone also causes interference but with heatsinks you don't have much of a choice because you don't have a shroud.

[jinu117]

condensers for refrigeration is much less restrictive than radiators for water cooling. Push and pull will gain almost nothing per noise level increase.

[johann]

push/pull only causes interference and much noise.

push alone also causes interference but with heatsinks you don't have much of a choice because you don't have a shroud.

Yes that is why I started the thread because the results showed this, much noise but no improvement. I did see Decrease in performance when using push/pull

SO ALWAYS USE ONE FAN PULLING!

[aussie_guy00000]

one more time, ALWAYS pull air. Think of the physics of moving air....... why does it moove?

fan or blower simply changes the static pressure from one side to the other. since "mother nature" always likes a equilibrium all you need to do is lower the static pressure on one end of the case and air will rush in to fill it. the greater the pressure change the faster the air will move.



I used to work as apprentice mine engineer and we pulled air down a elevator shaft 360 feet then 4 miles to the face and 4 miles back out. you could never push air that far, but lower the static pressure at the exhaust and mother nature takes over........... we did use a 3000 hp 5 blade propeller fan. fan sounded like a airplane...it exhausted sideways and there wasn't a leave on the trees for 150 ft, except for the tree tops.

edit :the last sentence I posted in the other thread posted here too. don't know how that happened. when I hit save it took quit awhile to post.

Not that i'm saying you're wrong, but your logic also applies to the push configuration. Air moves due to a pressure difference, in push config, the fan creates a high pressure area before the rad, and due to there being less pressure on the other side of the rad air flows through the rad. I fail to see why your theory proves that pulling is better, although I do agree with you. If you think of it theoretically, you can only lower the pressure to 0 atm, you can't possibly go lower then that, you can however create as higher pressure head as your fan can provide, i.e great pressure difference therefore high flow rate. Just a thought

[jinu117]

Not that i'm saying you're wrong, but your logic also applies to the push configuration. Air moves due to a pressure difference, in push config, the fan creates a high pressure area before the rad, and due to there being less pressure on the other side of the rad air flows through the rad. I fail to see why your theory proves that pulling is better, although I do agree with you. If you think of it theoretically, you can only lower the pressure to 0 atm, you can't possibly go lower then that, you can however create as higher pressure head as your fan can provide, i.e great pressure difference therefore high flow rate. Just a thought

Actually reason pull works better usually is only 1 reason... :P Shroud.... shroud makes the fan's dead zone more available to let air flow through. By same token with shroud you can also minimize the dead zone with shroud on push config. However, due to nature of even(ner) distribution of airflow on pull with good shroud, typical cases, pull works better. As for air cooling compressor, well, maybe more "directed" airflow but not more airflow over compressor....

[hincó]

http://forum.tweak.pl/index.php?showtopic=182498&hl=
pushing :]
klik on link..
there's a test one user (owner of shop) made
table shows temperatures...
Hope you know which temp is push (pchanie) and pull (ssanie)

[Jort]

Today i noticed something wierd.

I was testing a supercharged mach1 with some 200W heatload.

now the mach1 fancontroller sucks so i tought i'll place another 120MM in front of the condensor.

Temps rized almost instant to -21



so i prefer Pulling!!

Yes that is why I started the thread because the results showed this, much noise but no improvement. I did see Decrease in performance when using push/pull

SO ALWAYS USE ONE FAN PULLING!

your not alone m8

[johann]

My condensors have great shroud on both sides that is why I tested push/pull but I found single fan pulling worked better than 2 x the same fans pushing and pulling.

That is my experience. 1 fan pulling works best for me.

With push/pull noise was BAD, like the pulling fan is obstructed by the pushing fan

[jinu117]

Basically imbalance of fans acting as badly tuned windtunnel is causing the noise really...
As for mach I experimenting... Unless you shrouded the extra fan, I suggest not putting heat load when you drastically change airflow around condenser. Keep in mind system is hunting for balance and while under load giving too much variation on condenser temp all of sudden can cause sudden drop of temp until system recovers. Just like suddenly giving jort of extra refrigerant on suction side while load testing will give sudden 8c increas or so of temp while tuningthe unit. Lot of people who used to bench used extra fan outside winter day (at least in S. Cal) to give them extra kicks. As long as we don't have condition where fans our counter acting each other (which isn't the case if you just place a fan to aid in flow like mentioned... you will basically have better temperature unless condenser is already taking out 100% of heat (which certainly isn't the case)

[Jort]

yeah but its wierd, i'll test it later today with 15 min break push pull setup.

i am sure interested in the results, and i agree with you.
no way that condensor is small enough to handle all the heat produced by that unit.

greetz,

[Unknown_road]

Basically imbalance of fans acting as badly tuned windtunnel is causing the noise really...
As for mach I experimenting... Unless you shrouded the extra fan, I suggest not putting heat load when you drastically change airflow around condenser. Keep in mind system is hunting for balance and while under load giving too much variation on condenser temp all of sudden can cause sudden drop of temp until system recovers. Just like suddenly giving jort of extra refrigerant on suction side while load testing will give sudden 8c increas or so of temp while tuningthe unit. Lot of people who used to bench used extra fan outside winter day (at least in S. Cal) to give them extra kicks. As long as we don't have condition where fans our counter acting each other (which isn't the case if you just place a fan to aid in flow like mentioned... you will basically have better temperature unless condenser is already taking out 100% of heat (which certainly isn't the case)

thats bs! the reason why temp rises when you add refrigerant is very simple, you increase suction pressure. nothing to do with balance. When you cool down your condensor more then the situation before the only balancing it does is decreasing suction pressure. Because of other compression ratio. It has absolutly no reason to increase.

Also a shroud doesn't stop the problem of a push/pull setup. The only way the fans aren't bothering each other is to use exactly the same kind of fans then calculate how much time it takes for the air from the push fan to reach the pull fan. Then calculate what angle the pull fan turns in that amount of time. Then set the push fan so it is that angle ahead of the pull fan. with other words just use a bigger pull fan when you need more airflow

[ayrtonsenna]

its not bs!. its just his slant on the question. lots of physics are involved and to a greater or lesser degree everyone is right to a point. no need to put peoples opinions down i think, though i know what you mean in your point.
in large industrial water chillers, like the ones i use at work, the fans are housed at the top of the units and the heat exchangers are built into the side of the units and are infact the whole length of each side. air is drawn in through the radiators and pushed out the top. so in effect sucking. this is the optimum use of the cold air in and the warm air out at the top.