Thread: Quick questions about Chillers...

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So basically, I have some questions about the reasoning behind parts used in the popular instruction guide found here.
1. What is the reason for using screen wire to run through the center of the chiller? Is it because the metal easily conducts cold temperatures? Or because the gaps allow direct connection with the ice?

2. Why is the fogger situated on top of the chiller? Wouldn't you take more advantage of the velocity by having it shoot directly into the chiller?

I wasn't able to find particular reasons for the above, and I wanted to see if I could possibly improve on the design. However, I would like to know these two before I continued.

The screen allows the fog to "mingle" with the ice thus cooling it better then just having it shoot straight thru.
As far as machine on top I am not positive but I would guess its to make it more compact.

There's been some experimenting done on the forums recently with different fog chillers. In the chiller design you referenced, I can only see that the screen keeps an unobstructed path for the fog through the ice. The problem with this design, in my opinion, is that the fog will blast through the chiller without being chilled. Some fog will mix up with the ice and exit the exhaust chilled, but the majority of the fog produced will exit with very little chill.

There are a number of designs out there. My preference is one that gives the hot fog space to expand and then rise. When it rises and contacts ice, it will chill and fall. Then it will exit the exhaust. My theory is as well, that you want to minimize the mixing of warm and chilled fog. A chamber that has ice should be separate from the chamber where the hot fog expands.

This all works pretty well, but the bigger the fogger you have the more the fog can still be "blasted" through your chiller, no matter how you build your separate chambers. What helps from this point I believe is slowing down the chilled fog exhaust. The easiest way to do this is to attach the open end a big trash bag to the exhaust, lay it flat and then cut off the bottom edge of the bag. This puts some resistance on the flow of the fog and I think makes it spend a little more time in the chill chamber of the chiller AND makes it exit into the air more slowly. This slow exit into the warm air I believe helps the fog to retain its temperature and stay closer to the ground. The bag also makes the fog exit in a flat pattern that rolls nicely across the landscape.

Thanks for the replies. I had figured that that was at least part of the reason a screen was used.

@buckaneerdude
Then I assume that the absolute key thing here is direct contact with the ice? I wonder, then, if a design that forces the fog straight through the ice could be used. Thanks, I'll look into it.

Originally Posted by brombones

@buckaneerdude
Then I assume that the absolute key thing here is direct contact with the ice? I wonder, then, if a design that forces the fog straight through the ice could be used.

I want to try this also.

buckaneerdude -I'd be interested in seeing the design you built/ are talking about. Is there a link you could provide?

brombones -I built the chiller in the link you provided. I will try it for the first time this year. I may try it before Halloween, or may not because I'm busy with other props. But to the point Buckaneerdude was making -the modification to the design on this chiller that I've seen is to insert an obstruction into the wire mesh "pipe". I have a plastic disk (lid from a coffee can) I'm going to insert about 1/2 way thru the wire mesh pipe. The idea is to 1.) slow the fog and 2.) force more fog thru ice before it exits.

I also agree that slowing the speed down as much as you can and still get the volume you are looking for is a good idea. I'd be careful about how you do that though. You don't want backpressure on the fog machine, they are not built for that. I plan to slow mine by having it travel thru extra pipe, adjusting the length of that pipe as needed to get the right flow rate.

Lastly, you may want to consider using perforated drainage pipe. I just got a 10' length at Home Depot for something like $7, and it does a great job of spreading the fog over a wider area.

Good luck!

I won't have a chance to test this myself this year, but how do you think it would work if you used metal pipe inside the chiller? Make it all zigzag back and forth with just enough room for the ice to fall down to surround it on all sides. That way the entire pipe eventually becomes a cooling surface.

The other thought I've had being to simply buy the smallest deep freezer you can find and drill (well placed, so as not to cut through electrical or coolant lines) holes into it for the fog to go in and out of. Maybe do the same thing with metal pipes.

Originally Posted by rxnb90

buckaneerdude -I'd be interested in seeing the design you built/ are talking about. Is there a link you could provide?

brombones -I built the chiller in the link you provided. I will try it for the first time this year. I may try it before Halloween, or may not because I'm busy with other props. But to the point Buckaneerdude was making -the modification to the design on this chiller that I've seen is to insert an obstruction into the wire mesh "pipe". I have a plastic disk (lid from a coffee can) I'm going to insert about 1/2 way thru the wire mesh pipe. The idea is to 1.) slow the fog and 2.) force more fog thru ice before it exits.

I also agree that slowing the speed down as much as you can and still get the volume you are looking for is a good idea. I'd be careful about how you do that though. You don't want backpressure on the fog machine, they are not built for that. I plan to slow mine by having it travel thru extra pipe, adjusting the length of that pipe as needed to get the right flow rate.

Lastly, you may want to consider using perforated drainage pipe. I just got a 10' length at Home Depot for something like $7, and it does a great job of spreading the fog over a wider area.

Good luck!

I have a 25' length of drainage pipe that I use with my foggers. You get a nice effect even without the chiller, but it's 10x better with the chiller.

Zig-zaging pipe inside a chiller was my first thought. That would probably work fine. But for MAXIMUM cooling, it's all about the surface area. The volume of fog making direct contact with the cold would be much better by forcing it thru the ice it's self.

Also, make sure the chiller is the last step before the fog exits to it's distribution point. In other words, if you use a long length of pipe in your system, try to make it first in line. The reason is the fog will lose some heat just as it travels thru pipe. Let it do that, then put it thru the chiller. That should get the lowest overall temperature fog, and also help your ice in the chiller last all night.

One other point I picked up from other posts -someone suggested watering the grass, if you are rolling fog over grass. I've not tried that myself, but I think it sounds like it might make a little difference for the better.

Disclaimer -all my input is based on what I've read. I bought a fogger and built a chiller just this year. So I've not actually tried most of this.