Calling all engineers!!

[sar_dog_1]

Hey all! I am in the process of building a counterflow chiller out of my old 3/8" IC.

I was hoping an engineer could help me with an idea.

Would putting a restricted orifice at the discharge help with increased cooling efficiency? What would the effects of putting back pressure on the system be?

Thanks in advance and happy brewing!!

 

[jgalati]

Cooling efficiency is due mostly to the speed of the liquids. Restricting the output might make the coolant feel hotter at your exit port, but the amount of BTUs your removing from the boil kettle will be less than if you cranked your chilling water full bore.

 

[muhteeus]

Cooling efficiency is due mostly to the speed of the liquids. Restricting the output might make the coolant feel hotter at your exit port, but the amount of BTUs your removing from the boil kettle will be less than if you cranked your chilling water full bore.

I agree. If you want to improve performance you need colder (or faster absorbing) coolant, or more flow.

Easiest, get a pump for your water!

 

[sandyeggoxj]

My understanding was that the restriction was a way to force full contact area of the wort without having a pump. If there isn't a restriction then it is likely to have a bunch if airspace which is very poor at exchanging heat.

 

[masonsjax]

I've never seen air bubbles in the outlet hose of my unrestricted chiller.

 

[kevinb]

Decreasing the flow is bad idea. The amount of heat trasnfer you get depends on the difference in temp between your wort and your cooling water. The cooler the water is inside the heat exchager the more heat you will pull out of the wort. Having a restriction in the pipe will make the water coming out feel warmer because it was i contact with the wort longer, but that is actually less efficient from a heat transfer perspective becuase you have a smaller difference in temp.

 

[Blitzkrieg]

Another idea is to feed your counterflow chiller from the bottom up, seems counter intuitive as the hottest wort will be at the top but this way ensures that all the air is flushed out of the system as soon as the water reaches the end. I made mine so I can switch it back and forth, and without any empirical evidence I feel like it's flowing more smoothly from the bottom up...

 

[bja]

My understanding was that the restriction was a way to force full contact area of the wort without having a pump. If there isn't a restriction then it is likely to have a bunch if airspace which is very poor at exchanging heat.

This is all a bunch of crap. I hope you don't take advice from this source very often.

 

[rpe290]

My understanding was that the restriction was a way to force full contact area of the wort without having a pump. If there isn't a restriction then it is likely to have a bunch if airspace which is very poor at exchanging heat.

If it was me, I might just put a ball valve or something after the chiller? Control your flow that way...I use immersion+pump so not sure, just an idea...

 

[johngaltsmotor]

As others have said, the orifice will restrict flow, which will reduce the flow rate and increase contact time, which will increase the temperature of the exiting water (or reduce temp of exiting wort depending on which you are restricting).
The problem is that you really would rather vary flow over time. Initially when wort is hot you want a high volume flow to keep your temperature difference high (run too slow and the water exiting is the same temp as wort). But once the wort cools you can decrease the flow rate because your temperature differential from inlet to exit is nearly constant.
The backpressure won't make any significant difference (unless you have faulty joints).

 

[Thedutchtouch]

cooling efficiency is not what you want, you want maximum cooling per unit of time. use the coldest water you can, at the highest rate you can. the greater the delta between the cooling liquid and the cooled liquid, the faster it cools.

this is (somewhat) why we use ice cubes in drinks, rather than adding water at near the temp you want the end result to be.

 

[sandyeggoxj]

This is all a bunch of crap. I hope you don't take advice from this source very often.

Thanks for the correcting me with useful information. "My understanding" != this is the fact. I know that if you plumb a CFC or plate chiller in a way that you don't have the full internal volume filled with liquid then you are not using all the available cooling area. The suggestion to push the wort from the bottom up is good because it accomplishes the same thing as the restriction but in a more efficient manner. Next time you tell me that I am wrong please give an explanation. Your comment didn't enrich this at all. It is the internet after all, you can't just believe anything you read. That goes for anyone on this board, even the "experts."



Back on topic...
What is the best way to minimize fresh water use where time isn't a variable? Say I have relatively cool groundwater @ 50*f and I don't have a cooled resivore and pump to recirculate cool chilling water and I want to minimize how much fresh water I use in cooling my wort. Just size the contact area up to significantly oversize?

 

[bja]

I know that if you plumb a CFC or plate chiller in a way that you don't have the full internal volume filled with liquid then you are not using all the available cooling area. The suggestion to push the wort from the bottom up is good because it accomplishes the same thing as the restriction but in a more efficient manner. Next time you tell me that I am wrong please give an explanation. Your comment didn't enrich this at all. It is the internet after all, you can't just believe anything you read. That goes for anyone on this board, even the "experts."

Here's what you do. When you first turn on the coolant water supply, turn it on the whole way for a couple seconds. I guarantee this will clear all the air from the chiller. The you can back it down to a reasonable flow rate and begin chilling.

 

[masonsjax]

The returns diminish as the temperature differential narrows. If the goal is to chill as fast as possible, run the coldest water possible as fast as possible for the duration. If water conservation is also important to you, you could slow the rate down as the wort cools. Some folks recirculate the water, or even just save it to use as cleanup water.