# Fog Chiller



## bkr1969 (Nov 29, 2009)

Yet another project begun. This one from Chuck Rice at http://www.wildrice.com/Halloween/Construction/FogChiller/

The design allows for a maximum surface area for cooling the fog. I'm trusting that it will chill it down to my desired level.

The first step was twisting the copper around the PVC forms. The 20 feet (instead of the listed 25 since that what Lowes carried) of 1/4 inch twisted easily around the 1.5 inch form. The 50 feet of 3/8 inch was much harder around the 3 inch. Here they are in their compressed coil forms.


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## bkr1969 (Nov 29, 2009)

Next, the coils were expanded to the length of the vent pipe used, 2 feet. The larger coil was nearly there so it didn't require much stretching. Then the smaller coil was suspended inside the larger using zip ties at three points throughout the length of the coils. I inserted a long wire with a loop on the end to catch the ties in the middle of the coils. It took a bit of finesse, but in the end the small coil was perfectly suspended inside the large one.










On one end I made sure to align the ends of the coils where they'll be connected with plastic or rubber tubing. The other end didn't line up as well, so it will be the inflow/outflow end.


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## bkr1969 (Nov 29, 2009)

Before hanging the coils in the stovepipe, you need to drill any holes and do any mounting to it that you plan. You won't be able to get your hands inside after the coils are in place. The pipe I used was 6 inch diameter, 2 feet long. I found a gate handle to mount for easy carrying.









Next, I drilled the holes for hanging the coils. I used one large hole for each pair so the zip tie end would fit through. I looped the ties around the four appropriate spots on the large coil then slid it into the pipe.


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## bkr1969 (Nov 29, 2009)

The two end pairs weren't too hard to fish the ties through, but I cut up my hand a bit trying to get the inner pairs done. They eventually went through and I cinched them up so the coils were hanging in the center of the pipe.










The weight of the coils was deforming the pipe and causing the coils to rest on the bottom rather than hang. I cut a brace from some scrap aluminum stock that I had and just attached it to the end to help hold the shape. You can see how the coils hang from the center. You can also see the small length of tubing that connects the coils. It's held on with some hose clamps.


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## DaveintheGrave (Feb 12, 2004)

Wow, that's some chiller! Looks like it's going to turn out great!


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## TitanBry77 (Aug 6, 2012)

This is a very neat idea. I would like to see how it all attacheds, is the fog machine going to blow through the metal stove pipe? And at the other end what is connected, the site is a bit vague on what to use at that end. I work in HVAC so I have most of this stuff available right in my shop so it really peaked my interest! Good work!


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## bkr1969 (Nov 29, 2009)

The original link I posted didn't have specific details about the entry/exit either. I assume the fog machine outlet simply rests inside the pipe and the exit force is enough to move it through. I will test it to be sure, and if not, I will probably hook up a computer fan to the other end to suck it through. I just don't want it to move through too quickly because I want maximum cooling.

I just got another length of tubing at work the other day, so all I need now is the cooler and pump. I'm going on vacation in a week, but will be ramping up all my projects when I return.


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## dariusobells (Sep 24, 2007)

Are you using straight water for your cooling medium or are you sub cooling with a brine / glycol solution?


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## TitanBry77 (Aug 6, 2012)

Very cool can't wait to see more. I've always done more of the lighting side but definitely want to do fog right this year. I am still not sure how the pump side works and what you are going to pump through it?


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## bkr1969 (Nov 29, 2009)

dariusobells said:


> Are you using straight water for your cooling medium or are you sub cooling with a brine / glycol solution?


Funny you ask. I know salt water would chill to a lower temp, but salt + copper = bad(?), so anyone feel free to chime in on what might be the best solution that an 80 GPM submersible pump and the copper coils can handle.


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## bkr1969 (Nov 29, 2009)

TitanBry77 said:


> Very cool can't wait to see more. I've always done more of the lighting side but definitely want to do fog right this year. I am still not sure how the pump side works and what you are going to pump through it?


If you look at the plans in the original link, it shows a cooler filled with [insert solution of choice here] that is pumped through tubing into the 1/4" copper coil, into the 3/8" coil, then back to the cooler. I have a friend who lost the lid to a large cooler so he's donating it. I'll just cover it with plywood or something which will also make it easier to cut entrance/exit holes for the tubing.


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## dariusobells (Sep 24, 2007)

Easiest solution to pump would be water. adding salt or glycol (antifreeze) will allow you to get colder than 32 degrees though if you are using an ice bath for your primary cooling you wouldn't even need to worry about that. on the other hand if you are using dry ice as your primary cooling you might be able to get your coil colder using a solution. 

Salt brine could degrade the copper over time but not enough to make it a real problem many ice rinks use it all the time in their chillers.


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## TitanBry77 (Aug 6, 2012)

So is this basically then you are submerging the pump in ice water? I have a submersible pond pump laying around and also a Beckett submersible pump we use to pump out flooded basements etc, one of those may do the trick.


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## Pumpkinhead625 (Oct 12, 2009)

I'm planning on building this type of fog chiller, but I have some questions for you refrigeration/AC gurus out there.

1) Other than making it easier to wrap the inner coil, are there advantages to using 2 different sizes of tubing? Are there any drawbacks?

2) Is there much of a difference in the cooling capabilities between the 1/4" tubing and the 3/8" tubing? 

3) If I use this double coil system, would it be feasible to use 3/8" tubing for both coils?

4) Would there be a significant increase in cooling if I use a seperate pump for each coil?


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## dariusobells (Sep 24, 2007)

I would surmise the 1/4 tube was used because it was easier to coil that small. the 3/8 tubing will have much greater heat transfer surface to cool the fog with. If you can get both coils out of 3/8 it would increase the heat exchange surface of the entire unit. 

Using a second pump for each coil would not do any more good than simply putting in a T fitting and using one pump to feed both coils simultaneously. The only draw back I see to that is you have to run a line from the fog discharge end of the chiller, not that big a deal 

feeding both coils in Parallel rather than series I would would want to put the chill water supply line at the fog discharge thus making this into a counter flow heat exchanger. this would maximize the heat transfer capability's of the unit.


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## bkr1969 (Nov 29, 2009)

My hands and arms were sore trying to coil the 3/8" around the larger form. I cannot imaging winding it to a 2" coil. With only a week 'til Halloween this year, I will not have time (again) to get this running, but over the next year time and money should both be much more available so I plan on finishing some started projects and expanding to some others. This project is high on my list.


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