# Cheap Fog Chiller



## heresjohnny

I am always on the look out for doing something cheap. I like the fog chiller design with the 10' section of 4" PVC full of ice, but gagged at how expensive 4" PVC has gotten. I have been keeping an eye out for cardboard carpet tubes at a local carpet place I drive by, and I have been seeing more plastic tubes lately. Then it struck me, these may be ideal to make a fog chiller out of. So I grabbed some, and will be seeing how cheap I can make a functioning fog chiller for. The tubes are approximately 4 1/2" in diameter.


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## ScareFX

Good find HJ. Those should work great. I've got two chillers, one made of PVC and the other is made of the corrugated black drain pipe. I fill them with frozen water bottles and they both work equally well.


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## heresjohnny

I was also thinking of the frozen water bottle idea. Its good to know that it works, thanks!


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## IshWitch

ScareFX said:


> Good find HJ. Those should work great. I've got two chillers, one made of PVC and the other is made of the corrugated black drain pipe. I fill them with frozen water bottles and they both work equally well.


Do you have pics? I would love to see how that works. How long does it last? I've seen the 4" pvc layout, and a friend who tried it (he works construction so had scavenged all the parts) said it didn't work. Then again, we live in FL so pouring ice down a pvc pipe doesn't last long when it is 80 degrees out! 

We have made a cooler chiller and find that our garbage can chiller was faster to make, lasts longer and was way cheaper, too! I bought a plastic garbage can with lid (dark green, so no painting necessary) from Dollar General for $7, a length of dryer tubing (forget cost, but cheap) and cut 2 holes near the bottom of the garbage can with a box knife, one on each side. I stuck an end of the tubing out each hole(hitting the exposed ends with some black spray paint), then fed it in a spiral from one end until it was all in the can. Making the other end go straight up then start the spiral down. I fill it with a couple of big bags of ice and it stays cold all night.


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## MrsMyers666

I have a PVC fog chiller as well. I used a metal pipe of some sort attached to the nose of the fogger and surrounded that with ice (it's cool enough here for just ice) and that all went down the middle of the PCV (4"). I put holes in the PVC so as the ice melted it just dripped out. In this pic you can see the PVC on the right a little. The fog stayed pretty good considering it was breezy here. I did have fog stay for a good 10 minutes at least in the area of the opening.


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## ScareFX

IshWitch said:


> Do you have pics? ...


Here's a pic of the original materials. But last year I just used the reducer and the 10 foot PVC. I changed out the water bottles once in 3 hours and it was a warm 70-degree Halloween in Virginia last year. I've also got some video of a test of the 4-inch black pipe. I'll try to get it into a web ready format and post it.










In this flash pic you can make out the black pipe between the stones. The fog hung low on the ground and oozed across into the neighbors yard. It looked wild.


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## IshWitch

Very cool! (literally)  
I should just try one, if the bottles last 2 hours, then that would be pretty good. One change out for 4 hours total ain't too shabby!


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## IshWitch

http://i5.photobucket.com/albums/y184/Baricuda/DSC00066.jpg

Here is the fog from my garbage can, which you can see behind the tree. I also have a tombstone that hides it, just depends on where I use it.


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## ScareFX

IshWitch said:


> http://i5.photobucket.com/albums/y184/Baricuda/DSC00066.jpg
> 
> Here is the fog from my garbage can, which you can see behind the tree. I also have a tombstone that hides it, just depends on where I use it.


That can makes good fog.


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## BuriedAlive

Ditto for me on the PVC chiller. I've got two and they both were easy to make and quite effective. I've got about forty 16oz. bottles in a couple of old coolers that have been full of water for 3 years that I freeze the day before Halloween. After it's all over, I just toss 'em back into the coolers and store 'em for the next year.


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## heresjohnny

One idea I had about the frozen bottles was to attach a couple of sticks or something to the sides of the bottles to hold them right in the center of the pipe, so the fog would have the entire surface of the bottle to cool against. 

Another idea I want to try is to use salt water in the bottles. I remember from my old chemistry classes that normal water ice bath basically stays at 32 degrees while the ice is melting, once the ice melts the temprature starts to go up. A salt water ice bath stays several degrees colder while the ice is melting.


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## Gloomy_Gus

I have never seen the water bottle idea. I made the ice-chest chiller last year which worked ok but not as well as I hoped. Maybe I'll try the water bottle approach.


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## gmacted

Here is a video and a how to for my cooler fog chiller.

Chiller Video

Chiller: How to


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## Sickie Ickie

Nice work


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## heresjohnny

gmacted that is a great video, your chiller design works very well.

Back to the el' cheapo chiller. I learned today that the 4" PVC fittings fit the carpet tube, how convenient is that! I'll have to make some pictures and work out a cost for this thing, it should easily be under $10. I have water bottles frozen in the freezer, gonna test drive this thing this afternoon with the fogger I just recieved from Jeff at Frightners Entertainment.


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## gmacted

I am very happy with it's performance, but it was somewhat expensive to make. Keep us informed of your progress. You can't beat under $10. I'd be curious how effective it will be on cool/cold nights. Where I live, it can be fairly cold on halloween night.



heresjohnny said:


> gmacted that is a great video, your chiller design works very well.
> 
> Back to the el' cheapo chiller. I learned today that the 4" PVC fittings fit the carpet tube, how convenient is that! I'll have to make some pictures and work out a cost for this thing, it should easily be under $10. I have water bottles frozen in the freezer, gonna test drive this thing this afternoon with the fogger I just recieved from Jeff at Frightners Entertainment.


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## heresjohnny

I'll be providing details soon, I had some things happen that require my attention for a bit. The preliminary test went very well, though I used only 2" bottles of frozen water (video can be seen here http://www.hauntforum.com/showthread.php?t=2761. The fogger is 700 Watt.

I plan on using the 3 1/2" water bottles for the real thing, which if I remember my geometry will provide a volume of 4 1/2" squared between the 4 1/4" pipe and the 3 1/2" frozen water bottles, which is slightly more than a 2" pipe would provide. However, if you can imagine a 3 1/2" frozen cylinder centered in a 4 1/4" pipe, it seems like that should provide a lot of cooling, especially down the length of a 12' pipe.

One difference from other PVC pipe chillers I have seen is instead of adding a T to the inlet for venting, I used 2" PVC for the inlet, and left an air gap around the outlet of the fogger and the 2" inlet pipe. barely any fog leaked out. I also found the large elbow at the end was not neccesary since I was using frozen plastic bottles there was no need to retain ice / water in the pipe.

The result is I will only need to purchase a 4" to 2" PVC reducer (I also found a "3 to 2" reducer works too, it fits snugley inside the pipe), and a short peice of 2" PVC (mine was about 2'). I will work up a complete how-to soon.


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## gmacted

The fog looks great! What was the outside temperature?



heresjohnny said:


> I'll be providing details soon, I had some things happen that require my attention for a bit. The preliminary test went very well, though I used only 2" bottles of frozen water (video can be seen here http://www.hauntforum.com/showthread.php?t=2761. The fogger is 700 Watt.
> 
> I plan on using the 3 1/2" water bottles for the real thing, which if I remember my geometry will provide a volume of 4 1/2" squared between the 4 1/4" pipe and the 3 1/2" frozen water bottles, which is slightly more than a 2" pipe would provide. However, if you can imagine a 3 1/2" frozen cylinder centered in a 4 1/4" pipe, it seems like that should provide a lot of cooling, especially down the length of a 12' pipe.
> 
> One difference from other PVC pipe chillers I have seen is instead of adding a T to the inlet for venting, I used 2" PVC for the inlet, and left an air gap around the outlet of the fogger and the 2" inlet pipe. barely any fog leaked out. I also found the large elbow at the end was not neccesary since I was using frozen plastic bottles there was no need to retain ice / water in the pipe.
> 
> The result is I will only need to purchase a 4" to 2" PVC reducer (I also found a "3 to 2" reducer works too, it fits snugley inside the pipe), and a short peice of 2" PVC (mine was about 2'). I will work up a complete how-to soon.


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## heresjohnny

I would guess it was in the upper 80's, but it was also breezy. I have just about found enough 3.5" water bottles to make the how-to.


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## shaunathan

we used the trash can chiller with metal dryer duct... the problem we had was that there were heat pockets in the system, where the ice acted like an igloo and heated the fog back up before it left the system... baring any solution to fix this problem, we may try the PVC pipe/frozen aquafina bottle trick this year... how long was your pipe in that pic scare FX?


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## slightlymad

we tried the 3" pvc last year the mistake we made was only putting a 400 watt fogger to it.


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## shaunathan

*runs to the garage and checks his foggers* 

I have two 400W foggers :/ so which diameter of PVC should I try? also how long was the chill pipe? 5'? less? thanks for the answers


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## slightlymad

I didnt experiment enough to know whether it was length width or maybe too much ice.
We just ditched it and put a bigger fogger and new chiller on this years list.


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## shaunathan

we'll run some experiments this year and I'll post here about it


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## mrklaw

Has anyone here tried the wildrice fog chiller? It has coils of cold water running through the tube that the fog passes through.

http://www.wildrice.com/Halloween/Construction/FogChiller/


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## heresjohnny

I have seen that chiller before, I bet it would be very effective, and expensive to make.

I have been thinking about the different designs, and it seems like the effectiveness of a fogger is based a few things; the surface area of the cooler compared to the length of time in the cooler (obvious, longer it touches the cold, colder the fog will get), the surface area of the cooler compared to the volume of the cooler (the smaller the volume compared to the surface area of the cooler, the more fog will be in contact with the cooler), and the heat transfer from the cooler to the fog. 

The copper tube design probably has the best heat transfer, the dryer duct through ice a close second, and the frozen water bottles third because the plastic, though thin is still an insulator. In regards to the surface area of the cooler to the length of the cooler, the PVC and duct coolers are probably equivalent if you compare say a 10' PVC cooler to a 10' duct. I don't know what the surface area of the copper tubing would be without a little math. Finally the volume of the cooler compared to the surface area of the cooler would favor the PVC becuase your squeezing the fog inbetween the frozen bottles and the PVC.

With all of that what is the best fogger? I have no idea, but I suspect from what I have read is that they all do a decent job if constructed properly. In terms of cost I think a garbage can or cooler and a decent length of duct will probably have a similar cost as a 10' length of PVC and a hand full of fittings, around $15 to $20. I have no idea how much the copper tubing one would cost, but I suspect it would be significantly more then the other 2. Thats why the idea of a fog chiller for under $5 and easy to make that works sounds so good to me.


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## Torgen

Been thinking about cooling theory, and it may be that if you have the pipe get wider towards the end, it will cool it some more. At first, I didn't think that there would be enough pressure to matter, but then remember having to use ratchet straps on my ice chest cooler last year due to the pressure the fogger made blowing the top open.

As a gas expands, it cools. But, you want to get it where it's going (a tube too long, and the cold fog doesn't get out, since the force of the fog being expelled from the fogger is expended.) So, you have to balance the cooler with the fogger. For example, last year, the 600W fogger overpowered the smaller irrigation pipe/frozen water bottle set-up I had, but the 1200W continuous fogger (which is really two 600W that "trade off" duty) choked on the longer setup.

From this experience, I'd say have the fogger you're going to use on-hand, and tailor the chiller to the fogger. If you build a trash can chiller, and the fogger is too powerful for it, add some PVC pipe or irrigation pipe with frozen bottles to chill it some more. (I prefer the 4" irrigation pipe, because it's flexible and black!)


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## heresjohnny

I am thinking that the way to tell if 3 1/2" bottles are too much for a 4 1/4" pipe will be if the fog backs out of the inlet. And I have no idea what the best fogger is. BUT if you can find a carpet tube and collect up some old plastic bottles, the only purchase you need to make is a 4"x2" or 3"x2" reducer to build the fogger, and you can always return the reducer. And the carpet tube is a dark gray (see the picture in the first post).

Okay, its been a while since thermodynmics, but I wonder if the thing about the gas expanding causing it to cool, because a cooling gas will contract. If the pressure is dropping (i.e. it moves into a part of the pipe where there is more volume), then the gas will cool. Now what I wonder is, if the gas cools as it moves down the pipe, the volume remains constant, so the pressure must drop. It seems like that would actually pull the gas along the pipe because the pressure further down the pipe is less then at the mouth of the pipe (my head hurts). I am no sure about all of this, just trying to puzzle it out. Another thing is that turbulance, such as I would suspect from a flexible drain pipe, will make it harder to push the gas through.:googly:


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## Torgen

you know, you're right! Why else would the cold fog "ooze" out the end, especially if it's on an incline?

Wonder if you can get a Nobel in Physics for fogger theory?


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## heresjohnny

Torgen said:


> you know, you're right! Why else would the cold fog "ooze" out the end, especially if it's on an incline?
> 
> Wonder if you can get a Nobel in Physics for fogger theory?


Thanks Torgen, that makes my head hurt a little less. Unfortunately, all theory is fun but it don't mean the fogger will work. Got to build it to find that out.


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## Dr Morbius

Torgen said:


> Been thinking about cooling theory, and it may be that if you have the pipe get wider towards the end, it will cool it some more. At first, I didn't think that there would be enough pressure to matter, but then remember having to use ratchet straps on my ice chest cooler last year due to the pressure the fogger made blowing the top open.
> 
> As a gas expands, it cools. But, you want to get it where it's going (a tube too long, and the cold fog doesn't get out, since the force of the fog being expelled from the fogger is expended.) So, you have to balance the cooler with the fogger. For example, last year, the 600W fogger overpowered the smaller irrigation pipe/frozen water bottle set-up I had, but the 1200W continuous fogger (which is really two 600W that "trade off" duty) choked on the longer setup.
> 
> From this experience, I'd say have the fogger you're going to use on-hand, and tailor the chiller to the fogger. If you build a trash can chiller, and the fogger is too powerful for it, add some PVC pipe or irrigation pipe with frozen bottles to chill it some more. (I prefer the 4" irrigation pipe, because it's flexible and black!)


Unless you add a fan to help push it through.


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## slightlymad

Now thats what I have been tinking about this year.
Fog machine with a large cooling area 25-50 gallon copper coil with pumped water a small fan to pull it through into a manifold for 4 small props. 
My only hang up right now is how to interupt the circuit on the fan. intermitten running


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## gmacted

Dr Morbius said:


> Unless you add a fan to help push it through.


I have read about a few designs that used a fan for distribution purposes, but they did not work all that well. It dissipates the fog more than it distributes it.

My cooler based fog chiller is based on the "Vortex" fog chiller design. It uses a "pseudo Venturi" to create pressure for distibution purposes. The output of the fogger is connected to the Venturi that forces the fog into the cooler. The bottom of the cooler is open air that allows the fog to expand. The hot expanded fog then rises into the ice cavity of the cooler where the fog is chilled. The chilled fog then sinks to the bottom of the cooler where the output is. The fog is then forced out of the cooler due to the increased pressure caused by the expanding fog from the input.

It's basically simple physics at work.

My chiller works great. It produces a ton of low lying fog even in cool weather. It's not hard to make. The most expensive part is the cooler itself (other than the fogger). See my previous post for a link.


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## heresjohnny

I tried the fog chiller this evening with the 3 1/2" frozen water bottles in a 4 1/4" in tube, that was 12' long. And it di not go as I expected. First of all, I am convinced that the fog being chilled as it travels down causes a lower pressure at exit from the pipe, so it actually sucks the fog away from the fogger. Second thing, it did not work nearly as well as a previous run with small bottles. Afte some thought I realized that by using larger bottles I was presenting a larger cold surface area but was also reducing the volume in the chiller, meaning the fog was in the chiller for a shorter amount of time, and it is obvious to me now that time in the tube is more important than having bigger frozen bottles. So, next experiment will be with centered 2" bottles.


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## Dr Morbius

gmacted said:


> I have read about a few designs that used a fan for distribution purposes, but they did not work all that well. It dissipates the fog more than it distributes it.
> 
> My cooler based fog chiller is based on the "Vortex" fog chiller design. It uses a "pseudo Venturi" to create pressure for distibution purposes. The output of the fogger is connected to the Venturi that forces the fog into the cooler. The bottom of the cooler is open air that allows the fog to expand. The hot expanded fog then rises into the ice cavity of the cooler where the fog is chilled. The chilled fog then sinks to the bottom of the cooler where the output is. The fog is then forced out of the cooler due to the increased pressure caused by the expanding fog from the input.
> 
> It's basically simple physics at work.
> 
> My chiller works great. It produces a ton of low lying fog even in cool weather. It's not hard to make. The most expensive part is the cooler itself (other than the fogger). See my previous post for a link.


I noticed in your link how-to, Gmacted, that you used a "Y" for the INPUT from the fog machine to the cooler. Does that allow air in? Describe Venturi as it applies to your cooler...I understand it's like an airbrush and produces a vacuum, but how is this done in your cooler?


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## Torgen

Yes, I used the "venturi" input last year on my ice chest chiller. When the fogger goes off and shoots the fog into the chiller, it sucks some outside air in through the venturi. That way, it isn't just pure 200+ degree "fog air" in the chiller, you have comparatively cooler outside air as well. It seems that the fog has more trouble moving without the venturi, as it's trying to "suck" air in as it blasts into the inlet pipe.


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## heresjohnny

I will have to try a venturi vavlve on the next experiment, see if it makes a difference. I watched your fog video again gmacted, that sure is sweet!

A venturi valve means I break the $2 mark, dangit!


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## Dr Morbius

This is a valve? I thought it was just a regular Y tube?


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## heresjohnny

Dr Morbius said:


> This is a valve? I thought it was just a regular Y tube?


LOL doc, I read about venturi, and I see now that I had no idea what I was talking about. Now I am wondering if when the fog gets in the 4" tube and encounters the bottles (neck first), thereby constricting the tube so to speak, if that is creating a venturi effect and actually accelerates the fog down the tube. Which we don't want happening, we want the fog staying in the tube longer. In fact, I think having a 2" inlet pipe, the area of the 4 1/4" pipe minus the volume of the water bottles should be greater than 2*diameter*pie, so the fog may actually decelerate some when it enters the 4 1/4" tube.

I am thinking of the effect where if steam is being shot through the tube with the reverse y in it, that will actually cause a vacum in the Y, and draw air in and mix it with the fog. What is that called?

So the foggers have at least 2 effects happening. Venturi through changing the volume of the channel the fog is passing through (both in the PVC fogger when it encounters the frozen bottle, as long as the mouth of the bottle faces the incoming fog stream, and the cooler chiller that gmactd describes when the fog enters the cooler), and a thermodynamic effect from the change in temprature in the fog. Did someone say this was simple physics?


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## Dr Morbius

heresjohnny said:


> I am thinking of the effect where if steam is being shot through the tube with the reverse y in it, that will actually cause a vacum in the Y, and draw air in and mix it with the fog. What is that called?


That IS the Venturi effect. The vacuum created by the low pressure if an accellerated medium draws the air in. Same principle as Carbeuraters and hose nozzles.


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## heresjohnny

Dr Morbius said:


> That IS the Venturi effect. The vacuum created by the low pressure if an accellerated medium draws the air in. Same principle as Carbeuraters and hose nozzles.


From wikipedia Venturi - Wikipedia, the free [email protected]@[email protected]@/wiki/Fileisambig_gray.svg" class="image"><img alt="Disambig gray.svg" src="http://upload.wikimedia.org/wikipedia/commons/thumb/5/5f/Disambig_gray.svg/30px-Disambig_gray.svg.png"@@[email protected]@commons/thumb/5/5f/Disambig_gray.svg/30px-Disambig_gray.svg.png "The Venturi effect is a special case of Bernoulli's principle, in the case of fluid or air flow through a tube or pipe with a constriction in it. The fluid must speed up in the restriction, reducing its pressure and producing a partial vacuum via the Bernoulli effect." The picture that goes along with this is







. You can see where the constriction causes a vacuum,so the fluid level in the pipe above the constriction is lower than in the pipe at the inlet because of the vacuum at the constriction.

If you look at this picture, from wikipedia about carburetors, you can see where the passage for the air is constricted, causing the venturi effect.









Now, what I don't see is were the constriction is with the y-tube. I still think this will suck in air, but not the venturi effect (though I am not sure enough to bet money :googly: )


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## Dr Morbius

uh huh.


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## gmacted

Dr Morbius said:


> I noticed in your link how-to, Gmacted, that you used a "Y" for the INPUT from the fog machine to the cooler. Does that allow air in? Describe Venturi as it applies to your cooler...I understand it's like an airbrush and produces a vacuum, but how is this done in your cooler?


I was very careful to call this a "pseudo Venturi". It's really not a Venturi, but exhibits many of the characteristics of one.

To answer heresjohnny's question, "Now, what I don't see is were the constriction is with the y-tube. I still think this will suck in air, but not the venturi effect (though I am not sure enough to bet money )"

The y-tube is the constriction. The high velocity fog comes out of the fog machine and is forced by the "open air" port on the y-tube and continues through the y-tube into the cooler (This creates a lower pressure in the cooler). The 2 1/2 inch pipe connects to a large air pocket in the cooler that allows the fog to expand. Do you see the constriction now? The pressure is lower in the cooler pocket and therefore, outside air is sucked (or forced into the cooler --> depends on your point of view) from the open air port from the y-tube. The lower pressure in the cooler allows the fog to expand (similar to the gas atomizing in a carburetor).

The "open air" port on the y-tube is like a vacuum cleaner. If you put your hand on it, you will feel the suction.

I think the main problem with a long thin tube filled with ice, is that the fog is not allowed to expand. If the tube is very long, the fog will recondense and turn back into liquid. I think the trick with this method is to have the correct ratio of air volume and ice volume along with the right length of pipe. The air to ice volume ratio I use in my cooler is 1/3 air, 2/3 ice (approximately). It seems to work very well.

I hope this explaination helps.


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## heresjohnny

Thanks for the post gmacted, this has been a very helpful thread for me. Yes I understand that the 'y' is the constriction. If I were to spend money on a fog chiller I am convinced that you have the right solution, but I'm still gonna see what sort of performance I can squeeze out of the cheap tube one.

Have you ever tried using frozen water bottles instead of ice in your fogger? If so what were the results?

Question about the psuedo venturi effect. In my test runs I have used a 2" pipe as an inlet, and left about and inch between the fogger nozzle and the pipe. Fog never escapes, so I am wondering if providing this gap and shooting the fog into the pipe is providing the same effect. I believe there must be some vacuum or fog would be coming out of the inlet.

I am planning another test run with smaller bottles (2" in diameter instead of 3 1/2") which will greatly increase the volume in the tube and slow the fog down. I am also going to experiment with leaving a gap between the inlet and the ice, which may provide somewhat of a chamber for the fog to expand in


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## Torgen

Take a small feather or something, and hold it next to the gap and you'll see it being pulled by the air getting sucked in. That's why many chiller instructions say to leave a gap between the nozzle and the pipe (if they don't use the "Y" )


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## gmacted

heresjohnny said:


> Thanks for the post gmacted, this has been a very helpful thread for me. Yes I understand that the 'y' is the constriction. If I were to spend money on a fog chiller I am convinced that you have the right solution, but I'm still gonna see what sort of performance I can squeeze out of the cheap tube one.
> 
> Have you ever tried using frozen water bottles instead of ice in your fogger? If so what were the results?
> 
> Question about the psuedo venturi effect. In my test runs I have used a 2" pipe as an inlet, and left about and inch between the fogger nozzle and the pipe. Fog never escapes, so I am wondering if providing this gap and shooting the fog into the pipe is providing the same effect. I believe there must be some vacuum or fog would be coming out of the inlet.
> 
> I am planning another test run with smaller bottles (2" in diameter instead of 3 1/2") which will greatly increase the volume in the tube and slow the fog down. I am also going to experiment with leaving a gap between the inlet and the ice, which may provide somewhat of a chamber for the fog to expand in


I have never used water bottles, instead of ice. I think surface area is the key here. Frozen water bottles may not provide enough suface area in my case. Last year, I bought all my ice (~60 lbs), but this year I've already started making ice for my chiller. It's cheaper that way. All you need is water, cold, and a place to store it.

I would guess that a gap between the fogger and the inlet would have somewhat of an effect, but it may be minimized.

Please be aware that I take no credit for this design. I did a lot of research before I built my chiller. I got most of my information from the deathlord.net web site and their Vortex chiller. Early last year, they had a page that descibed how their chiller worked, but removed it because I think it was hurting their sales. I am just sharing the knowledge I obtained and my understanding of it.

I am also sharing my "real world" experience with it because I think it's a very effective method. I by no means think this is the only method or best method or the most cost effective one. The bottom line is use whatever method works best for you.

I look forward to reading the results of your experiment.


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