Using a mini fridge for are chiller

[Frankiesurf]

So a friend of mine has a 3 barrel system. During the summer it takes him around two hours to knockout with a plate chiller. He does have an (I think) 25 foot 1/2" copper wort chiller that he wants to use but does not want to have to keep replacing ice and draining a barrel of warm water.

The chiller would fit perfectly in a mini fridge. My idea was to just plumb his hoses through the side and use that to pre chill.

My question is would this be efficient enough? I know it would be at least a little better than what he has but is it worth it? Would the copper stay cool enough without being submerged in water?

 

[Frankiesurf]

I really need proofread my damned titles before I submit.

 

[joshindc]

I'd say it's definitely not worth the trouble. You've got way lower heat transfer from the copper to the air vs copper to water, and the restriction of adding the wort chiller is just going to drop the flow through the water side of the plate chiller. It might even add time to the total process.

What I'd try instead is just using the immersion chiller. How warm is your tap water? I can knock the temperature of my wort down way faster than 2 hours in the summertime with a 25' 3/8 chiller, the half inch should be even faster. Just keep stirring the wort.

 

[Falcon3]

So your idea is to use the 25' immersion chiller as a prechiller for the water flowing through the plate chiller? If that's the idea, I don't think it will work very well. The ice water that you're pumping through the chiller currently has a relatively high thermal mass. If you put the ice bucket in the fridge, The air in the fridge won't help it from melting faster- you'll maybe notice a little slower melt of your chiller water, but not probably enough to make much of a difference.

If you're thinking that the chiller just sitting in the fridge by itself will help- it won't. Air temp will not transfer very well into the copper chiller at the speed you need it to.

 

[Squaregrouper]

I'm by no means a pro, but this works very well for me and I kill two birds with one stone...
25' 3/8 copper immersion chiller with cold tap water (Maryland/Mid Atlantic temps)
Aquarium air pump with aquarium airstone

This method aerates the wort and keeps it moving to allow equal exposure to the chilling coil. It is a hands-off way to drop wort from boiling to ~65f in 30-40 minutes.
**Note- freshwater is abundant here, so the "waste" of 100-200 gallons of clean water is not a concern. Personally, I use the effluent/warm discharge to water my garden and lawn.**

 

[Frankiesurf]

Josh, the water here in NY is over 60 degrees. The problem is it is three barrels of beer, not a 5 or ten gallon batch and he already has a plate chiller. That wort chiller isn't effective.

Falcon3, your last statement is what I was curious about. That is what I thought but wasn't sure.

He is working on a glycol system but needs to speed up the process in the meantime.

 

[Bobby_M]

A mini fridge is runs about 150 BTU/hr. Let's see, it's capable then of dropping 15 gallons of water by 1 degree F over the course of an hour which will do exactly "jack ****" in a wort chilling operation.

The only way to use refrigeration for wort chilling is to build up a store of very cold water, glycol, or ice over a long period of time and then unleash it quickly on the wort. Ice is particularly effective because of the concept of latent heat. In other words, a pound of ice will cool much more than a pound of 32F water.

We've seen people use chest freezers as large coolant reservoirs for this purpose because it's already a tank as long as you seal all the interior seams and drains.

90 gallons of beer weighs about 800 pounds and you want to lower it from 212 down to 70F so that's 142 x 800 =114,000 BTU. If it's currently taking 2 hours, he's removing 57,000 BTU/hr. You can increase the speed if you can increase the coolant flow. If the chiller is the bottleneck, there's always a bigger chiller.

Being in NY, you have a lot of months available to use natural cooling to your advantage. If you can mount a 275 gallon IBC tote on the roof or outside filled with glycol at a rate that will keep it from freezing, you have a source of reusable coolant that will probably be colder than tap water for a good 6 months out of the year.

 

[Frankiesurf]

Thanks Bobby. I appreciate the information and will pass it on.

 

[joshindc]

Whoops, I must have missed the 3 barrel bit.

One thing to keep in mind with a plate chiller is that water temperature and water flow rate are both critically important, so sacrificing one for the other may easily be a wash in terms of cooling speed. I'm assuming you're pumping wort through adjusting speed with a throttle valve and using whatever water pressure you've got to push the water side as fast as you can? If this is the case than just buying another plate chiller that's the same size and hooking it up in parallel should cut your chilling time almost in half. They aren't cheap, but another chiller that's the same size should be cheaper than a bigger chiller.

 

[sandyeggoxj]

If you email Duda diesel or thermaline with your water pressure, temperature and flow rates they should be able to size a chiller for you. Something to consider .

 

[Sharper]

I don't have any experience with batches over 5 gallons, and don't have the math skills to figure out what volumes and flow would work for you but here is what works for me.

I am using an IC, but I assume a plate chiller would have much the same results, with a few changes in procedure

I first start with my ground water and my temps get into the 110 degree range within 10 minutes or so.

I then switch water sources. I use a cooler with a pond pump and circulate the cooling water. I use about 4 gallons of water and 20 lbs of ice, and I get to 64 degrees in less than 10 minutes, with ice to spare.

My thought for a 3 barrel would be to use the groundwater while circulating the wort back into the kettle until you reached 110-120 degrees, then switch to the cooler water. I'm guessing a 110 quart igloo with 20 bags might be enough. At the point you switch to the ice water, you would be transferring to the fermenter.

It would be a small investment to try out but maybe it would work??

 

[Bobby_M]

The tap water prechill before using ice or glycol is definitely viable, but on a scale this large, I'd want to do it simultaneously. Run the wort out of the BK into plate chiller #1 which is being fed with tap water. Then the ~100F wort exits that chiller and hits plate chiller #2 which is being fed icewater. Doing it this way means that you can run direct to the fermenters pretty quickly and you do save icewater. Whether that colder coolant is really icewater or prechilled glycol or 34F pure water really doesn't matter all that much. I would just use whatever cooling system is nearby and convenient. Is there already a walk in freezer for hop storage to be able to freeze buckets of water? Is it already 20F outside at the time where sitting buckets out overnight would do it? That sort of thing. If not, I think I like the chest freezer tank idea best.