4 chamber Semi-active Fog Chiller-Let the Insanity continue (You'll like this one)

[niblique71]

In my never ending (almost insane) quest to produce a better fog chiller, I began to question some of the concepts that I used in my own Scratch Built Fog Chiller which has become known at the "Cube chiller". It's a GREAT Chiiler with Proven effective results.

I've been trying to read the entire "Vortex fog chiller thread" but it so long that I've had a hard time getting through the entire thing. It has some GREAT information so far And I'm looking forward to finishing the read. A few universal flaws of all Ice type fog chillers began to emerge as a theme. They all EAT a LOT of ice.

I run my (3) chillers a LOT during the Halloween season and racked up a $350 bill between Ice and Dry Ice over a few weeks. If you Just use your Cube (or similar) chiller for one night, than it's No big deal (Cheap).


THE GOAL:
Make a reasonably priced (Not Cheap) chiller that will do the job using a fraction of the Ice/ Dry Ice.
Make it in a size and shape that it can easily be incorporated as a monument base or other halloween related prop.
Make it easy to Load up with cooling materials.
Make a chiller that will work in colder climates where you have to UBER Chill the fog to get it be "Ground hugging"


THE CONCEPT:
Use "free" cold halloween air to assist in the cooling process.
Use "Stages" to cool the fog in a progression from warmer to colder.
Totally Contain the fog from entrance to exit.
Ice and Dry Ice can be added during fogger activity.
Self Feeding Ice/ Dry ice reserve for lower nightly maintenance.
Capture the negative calories of the melted ice (Still has cooling properties)

STAGES:
Chamber 1 -Expansion Chamber
Chamber 2- Active air cooling (fan Assist?)
Chamber 3- Ice bath (75% Ice and 25% Water)
Chamber 4- Dry Ice, or Dry Ice and water ice mix

THE PROJECT (In Progress and UNTESTED):

Here is what I came up with so far.
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Hot fog will enter the expansion chamber (unfinished) in the foreground using 2"PVC and a 90 degree "Up Pipe".

The hot fog will expand. Via pressure it will be forced into the second "Air cooling" chamber through the 6 holes at the bottom of the panel in this view.

Again using the positive pressure from the fog machine, it will be forced up through the series of 1/2 cooper pipes that will be kept cool using a built in fan.

At the top of that chamber the fog will be forced into a "matrix" of copper tubes (Chamber 3) that submerge into an "Ice Bath".

Once the fog exits the ice bath, it will pass through a narrow transfer chamber to the Dry Ice chamber where it will recieve it's final cooling effect.

Add a plastic bag at the exit and there should be some very frigid fog carpeting the neighborhood.

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Here's a good shot of the "Air cooling" chamber yet to be enclosed. A Fan will be mounted in a chamber on the right to force cold "ambient" air through the first set of copper pipes.
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Partially enclosed. That thin slit is a transfer channel between the Ice bath and the dry ice chamber.
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Here it is more or less complete, I still have to decide weather I want to put the air cooling fan on the Top (inside a monument), or on the side. The "Ice access lid isn't installed yet. I'm going to use that lid area as a "Hopper". There will be a "Cube" of Ice and dry ice (Separated) that will rise above the main body of the chiller inside a monument. THis will allow me to "Overload" the cooling areas and let the Ice melt down. My hope is that the "Ice chamber" will hold water so I can get really good contact with the small copper pipe matrix.
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I just finished this stage of the chiller this evening. EVerything you see in this last picture is glued and sealed up. Nothing can be removed (except the ice hopper/lid, not shown). The entire thing is air/water tight (hopefully). The fog won't make direct contact with the Ice but will rely on trhe thermal properties of the copper to transfer the cold..

I'll let the PL Glue cure up and give it a trial run tomorrow or sunday. I want to test it while the weather is still cold, so I can get a good bearing on it's effectiveness. Of course if I lived in a warmer area, I wouldn't need to chill the fog to such an extreme to get it to stay on the ground.

WISH ME LUCK

[halstaff]

Looking forward to seeing the results of your tests.

[niblique71]

Here are some more "in progress" pics not in any particular order. Damn, I hope this thing is "Air tight".

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Note the Petcock in this picture. It to relieve some of the melted icewater and let the fresh ice drop down to replace it. That's the theory anyway. Tests soon.
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I realize that I might have some fog "Backwash" with this design (fog drooling out the entrance pipe between burst). I've accounted for that for future impovements if the design shows promise. It's Just a prototype for proof of concept. If it works as planned, I'll be thrilled.

BTW.. Copper is SOOOO DAMN EXPENSIVE Now!!!!!

[Wildcat]

Can't wait to see it in action. You've become obsessed with cooling fog. Our very own Mr. Freeze. LOL.

[niblique71]

OK, I could't wait. This concept has been festering in my brain for more than 3 years. I disobeyed my own rules and tested this thing before the glue fully cured with "JUST A FOGGER"...... NO ICE.... 28 degrees...I was just checking for leaks and it already has a STRONG indications that the design will be a winner, In fact I might have overdesigned it. Yea, I created a few leaks because the pressure was too great for the curing glue. It forced me to add a few deck screws to pull the thing tight, but if I was patient that wouldn't have been an issue. I'm TOTALLY Pumped!!! With the Ice/ Dry Ice combo this thing should really kick butt. The volume of fog output is a little less than I wanted.... but with some tinkering I think I can get that down pat. AND... the "Air cool" chamber was blocked off since I hadn't decided where I want to put the fan. NO Kidding, I'm PUMPED!!!

I "Cheaped out" in the prototype, opting for 3/8" OD flexible copper pipe. I should have used 3/8" ID or a little larger for the ice bath area. I can tell that the restriction of the flow is at it's limit even though it worked just fine with a 1000W fogger. Still cool though, it's proof of concept so far untill further testing..

[steveshauntedyard]

Nice! This thing looks really cool.

[Lunatic]

Wow Nibligue! Been busy there? Lot's of thought and time involved in that one my friend. Very nice to see your enthusiasm.

I was involved in that Vortex chiller thread years ago so I have lots of respect for your effort in this project. The thread is ridiculously long to read and I wouldn't want to do it but there's some great info in it. We can thank many people for developing the "Reverse Vortex" concept. But now it appears that you have sparked a new reason for a long thread.

Can't wait to see your results after loading that sucker with some ice. I love the concept of different cooling chambers with the final dry-ice cooling.
Good luck!

[niblique71]

It's 34 degrees out and a little windy, but I decided to give the chiller a try. I don't have any dry ice for the final chamber, but I filled that with water and Ice.

Good news part 1, The chiller does hold water in both chambers so I'm happy about that part.

The bad news is that it's 34 degrees out. I don't think I can chill the fog to a low low enough tempature using just regular Ice. The design appears to be working as the fog comes out thick and white and has ample volume. It just doesn't hug the ground due to turbulance and a lack of a tempature differential. In order to really test it I'll need about 2lbs of dry ice and a slightly warmer day. I might give it a try indoors just to see.

Halloween night here is typically 45-50 degrees. My guess is that I'll need at least a 15-20 degree difference (or more) between the ambient air and the chilled fog to get the desired results.

[Vlad]

I think you should have built in an ice cube maker.

[niblique71]

Originally Posted by Vlad

I think you should have built in an ice cube maker.

Perhaps your not far from the truth Ken. That's why I love your neverending sarcasm. Perhaps we can discuss some modifications when we get together next weekend. I didn't do this project to impress anyone. I had a concept that I wanted to prove or disprove.

I did some more testing last night and the concept DOES work. Granted it did NOT outperform my "reverse Vortex" in this current version. I used Ice in both chambers and did get low lying fog. It just wasn't that "Uber Chilled" fog that I was hoping for. With 2-3 lbs of dry Ice in the final chamber, I think the results will be comparable to the reverse vortex. The design shows promise, but needs some improvement to perform to my expectations.

OBSERVATIONS:

1) There are some chamber conflicts that I need to resolve to get optimum performance. But I knew this when I designed this version.

2) I feared that the expansion chamber was too small for a high wattage fogger. I think a slightly larger expansion chamber would create more fog volume. My results were't bad though.

3) I need a little more surface area for the pipes in the cooling chambers. This can be accomplished by Crushing 1/2" pipes into flattened ovals. This will give more surface area without restricting the flow much. Also by adding more pipes the flow will slow down even more and capture more "Cold".

4) I should have gone with my instincts and used 3" inlet pipe instead of 2". I just don't think enough outside air is being drawn into the chiller. I can always add a 2" to 3" adapter afterwards which might help with expansion.

5) I feared that the chiller would "Oooze" out fog between bursts since it's not relying on gravity like a reverse Vortex. It didn't. That must be due to the "90 degree up-pipe", and a little bit of convection.

6) Another concept occured to me that I haven't (yet) seen discussed in the "Vortex thread". Any chiller that makes direct contact with Ice does have this distinct advantage when cooling a gas (Fog). When the Ice melts it actually briefly get's colder as it changes states (I think I have this right??). You will also be taking advantage of some of the melted ice changing to a gas (evaporating a little bit)which contribues a little to the cooling as well. Conversely when you "Freeze" water into Ice, it releases heat. I won't be able to take full advantage of this principal since it's an enclosed system. My second test didn't use water in the main cooling chamber, just some leftover snow (Slightly melted). I think that the snow making contact with the copper tubes, and then melting a little bit actually dropped the tempature in the chamber by a few degrees. I ran it this way for 15 minutes. Then I added Ice cold water and let it sit for a while to "Chill down". The results were still good but noticably less once I added the water.

Conclusions:

The Idea works. In order to make it compete with the vortex, I will have to:

Increase the surface area of the individual pipes for better thermal exchange. This will make the pipes more like a radiator by flattening them into an oval (in the middle). Add even more (exchange) pipes to slow the fog speed down even more as it travels through the cooling chambers. This will also transfer a lot more thermal energy.

Make a (slightly) larger expansion chamber.

Improve the cooling chamber layout to resolve some minor thermal conflicts.

Check in to Greystone for a LONG rehab.


I'm not expecting ANYONE to try to build one of these. I'm doing it to satisfy my own curiousity. BUT if I can get it to work the way I envision, We'll have a viable alternative to the reverse vortex that uses a LOT less ice or Dry ice. It might also be usable indoors without the need for a tray to capture the melted Ice water.