Interesting conversation with a Mech. Engineer at Work

[JMD87]

I think the whole point to the OP is to maximize efficiency of a CFC. Sure you get your wort down to ground water temp when it comes out of the regular CFC, but how can we do the same thing using the less material & water? That's what efficiency is.

If we really wanted to we could build a whole elaborate refridgeration system that will get the wort to 70* in no time. It wouldn't be more cost efficient then a regular CFC though.

 

[PseudoChef]

I think the whole point to the OP is to maximize efficiency of a CFC. Sure you get your wort down to ground water temp when it comes out of the regular CFC, but how can we do the same thing using the less material & water? That's what efficiency is.

If we really wanted to we could build a whole elaborate refridgeration system that will get the wort to 70* in no time. It wouldn't be more cost efficient then a regular CFC though.

Right, but you're not going to do that through re-design of the chiller. You will do that through finding a way of cooling the incoming water out of the tap. Nothing doing with the actual chiller.

 

[JMD87]

Right, but you're not going to do that through re-design of the chiller. You will do that through finding a way of cooling the incoming water out of the tap. Nothing doing with the actual chiller.

I kindly disagree. That's like saying we can't make our automobiles more efficient without using a different engine. Cars have become so efficient over the past 20 years, and it's because we keep trying to improve an existing design.

 

[Anthony_Lopez]

Few things, a plate chiller isn't really a CFC by any means. A plate chiller is set up to have a layer of cold water or cooling liquid sandwiched next to a plate of hot wort. The more sandwiches you make, the more efficient it becomes. The whole idea of the plate chiller is surface area of hot wort being exposed to a cooling liquid.

A "tube in shell" design is not a CFC either. This "hybrid" design is meant more as a reverse immersion chiller.

Don't forget, CFC means COUNTER FLOWING liquids. This counterflow design increases the efficiency.

As to what others have said regarding temp. differentials, etc., the whole point of trying to push the envelope on the CFC designs is from looking at HEX systems that the military currently uses. Obviously I can't tell you what they are, but this idea of mine mirrors one to some extent.

Obviously you cannot cool a hot liquid past the temperature of the cooling liquid, however if we can get to that thermal equalibrium faster, why would that be a problem? In the end it all comes down to a ratio of efficiency to cost. A standard CFC can be easily built, and it works, but why not try and make it work better? It's quite hard for people to DIY a plate chiller, however a CFC that costs the same as a plate chiller retail and is as effective as one, while being able to build it yourself seems like my ideal product...

 

[PseudoChef]

I kindly disagree. That's like saying we can't make our automobiles more efficient without using a different engine. Cars have become so efficient over the past 20 years, and it's because we keep trying to improve an existing design.

There's no way to use 70 degree water to chill wort to 65. You cool the water to 65, then you can chill wort to 65.

 

[Anthony_Lopez]

Right, but you're not going to do that through re-design of the chiller. You will do that through finding a way of cooling the incoming water out of the tap. Nothing doing with the actual chiller.

Thats the only way you could make the chiller more efficient... By lowering the temperature of your cooling water, you aren't increasing efficiency.

I suppose it depends on your definition of efficiency, however in my mind, I look at it like this: How can I make product "A" do the same thing it already does faster, without changing its input and output. The only way to do that is by changing the way it works. The whole principal of an HEX is to heat up or cool down a liquid by means of heat transfer over a large surface area.

 

[Anthony_Lopez]

There's no way to use 70 degree water to chill wort to 65. You cool the water to 65, then you can chill wort to 65.

Thats not what I'm trying to do. Lets assume that I can chill 212*F Wort to 70*F in 15 minutes using 70*F tap water.

Thus, (212-70)/15 would be my efficiency.

Now, I want to make (212-70)/(15/2)

Thats what I'm trying to do. I don't want to change the water temperature, I just want to increase efficiency.

 

[sigmund]

Psst, a plate heat exchanger and a tube in shell are both counterflow applications.
The coolant runs the reverse of the liquid to be cooled.

 

[Anthony_Lopez]

I would agree as for the plate exchanger. What would be your definition for a tube in shell application in home brewing?

 

[PseudoChef]

Ok, then that will depend on the flow rate of the wort. Are you using a pump or gravity?

 

[Anthony_Lopez]

Lets assume flow rate is the same across the board, regardless of pumping or gravity.

 

[SILVER13ACK]

I would agree as for the plate exchanger. What would be your definition for a tube in shell application in home brewing?

A copper tube enclosed in PVC pipe.

***NOT***
Sticking an IC in a bucket of ice water. Thats called 'sticking an IC in a bucket of ice water'.

A tube in shell is just that...an tube in a shell with counter flowing liquids. The CFC that you speak of and that everyone uses can also be classified as a tube in shell. Or to be more precise, a tube in tube. But its the same exact principle.

 

[Anthony_Lopez]

its actually not the same principle.

A tube in shell would be in an enclosed pipe, however there is no way for the counterflowing liquids to be controlled. Yes, you can have water going in the bottom of the shell and out the top of the shell while the wort flows through the tube from the top to the bottom output, you are not forcing a counter-flow exchange across the entire surface area of the tube. This "tube in shell" would be a hybrid chiller, which is less efficient.

Water pressure ensures that you are getting a full counter-flowing heat exchange inside a CFC.

 

[Anthony_Lopez]

 

[SILVER13ACK]

its actually not the same principle.

A tube in shell would be in an enclosed pipe, however there is no way for the counterflowing liquids to be controlled. Yes, you can have water going in the bottom of the shell and out the top of the shell while the wort flows through the tube from the top to the bottom output, you are not forcing a counter-flow exchange across the entire surface area of the tube. This "tube in shell" would be a hybrid chiller, which is less efficient.

Water pressure ensures that you are getting a full counter-flowing heat exchange inside a CFC.

It is the same principle. There are several differnent types of tube in shell.

If you have a straight tube in a straight PVC pipe, then you have the exact same thing as a 'tube in tube'. It doesn't matter if its in a coil or if you have a 25' long piece of PVC with a 25' piece of copper tubing running inside of it.

You can also have a manifold of straight pipes running inside the tube, etc etc. It is still a CFC. I didn't say it was more or less efficient, but it follows the same principle. With every design, there are variables such as flow rate, pressure, etc...but it's still the same principle.

 

[JMD87]

That's an interesting design. Did you calculate to see if you have greater surface area by having a bunch of straight tubes as opposed to a single coil within that "shell"? What are the dimensions of that system (more specifically the copper on the inside and the ID of the shell itself)?

 

[SILVER13ACK]

Take a Chillus Convolutus, run the wort in the outer tube, cooling liquid in the inner tube(running the opposite way), and stick the whole think in a PVC pipe with a small gap around the convolutus, and run water in the opposite direction of the wort. Put a solid PVC pipe in the middle of the convolutus so water isnt wasted doing nothing in the middle. Also, that would increase water pressure.

I bet you $10 that it's more efficient than just using the convolutus in the normal way. You can probably cut the chiller down 33% and still get the same cooling efficiency(just a random guess, I have no idea). Yes, I know it would not be as efficient as if you had 3 closely coupled tubes, but it's more efficient than just the chiller by itself, probably cheaper and easier to make than using 3 tubes. But I dont know.

 

[blacklab]

Is this really necessary given that your typical CFC or plate chiller can take the wort from boiling to 75-80 ish in one pass(given that the cooling water is proper temp)?

Who cares?

 

[JMD87]

Is this really necessary given that your typical CFC or plate chiller can take the wort from boiling to 75-80 ish in one pass(given that the cooling water is proper temp)?

Who cares?

the whole idea of this is to try and come up with a cfc that doesn't need a pre-chiller. If everyone just accepts what they already have, then we would lose all drive to try and increase efficiency in every thing we do.

Convoluted CFC's already exist which do increase the turbidity of the cooling water.

This is how mankind progresses. It may be a little insignificant experiment to some people, but experimenting and pushing the limits is why we're all typing on a computers right now. If you don't care it's better to not respond. I personally (as well as others I'm sure) find things like this very interesting.

 

[Anthony_Lopez]

I completely agree JMD... comments like "who cares" kind of negate my entire career...

 

[Brew-Happy]

When I read about CFC chillers I can't help but think of this idea. Basically it reduces the cross-sectional distance in one direction, exposing the wort equally to the cooling water. Therefore a lower thermal gradient across the wort as it flows.

This is similar to your water/wort/water idea but simplifying the design.

I added the sinusoidal curves to cause turbulence and hopefully reduce laminar flow issues.

The original tubing would have regular round ends, just crimped midsection. I had even thought about making a U so that the length of the chiller would be ~ 1/2 as long.

I like these geek debates on how build a better mouse trap!! Keep it up

 

[Anthony_Lopez]

here we go!

That would work well in a tube in shell design I'd bet...

 

[JMD87]

When I read about CFC chillers I can't help but think of this idea. Basically it reduces the cross-sectional distance in one direction, exposing the wort equally to the cooling water. Therefore a lower thermal gradient across the wort as it flows.

This is similar to your water/wort/water idea but simplifying the design.

I added the sinusoidal curves to cause turbulence and hopefully reduce laminar flow issues.

The original tubing would have regular round ends, just crimped midsection. I had even thought about making a U so that the length of the chiller would be ~ 1/2 as long.

I like these geek debates on how build a better mouse trap!! Keep it up

Thats a nice practicle idea. Where would you get the "coil" from? Is that something that could be bought off the shelf? I think one thing that needs to remain the same is the ability to go to home depot (or maybe some internet source) to purchase all of your materials. Nothing should be specially made.

Also, I would try to keep it gravity fed. Looks like you might need a pump for that. With a little tweaking that could be the new CFC we're looking for.

I would go right for option #2. Not only does the sinusoidal curve create turbulance, but it increases the amount of surface area within the chiller. "The shortest distance between two points is a straight line" - Now go do the complete opposite!

 

[Anthony_Lopez]

this would work well in the closed pipe setting, but I'll be damned if I tried to put that through a hose...

 

[Brew-Happy]

I wasn't thinking of using anything special with this. I would take a coil of tubing and straighten it out, then crimp/flatten the midsection of the tubing. It would probably be best to fill the tubing with sand to prevent crushing. If you happen to have a friend with a great machine shop, they would have a rolling press to flatten something such as this. I don't have such a friend, but I would try to find one.

As far as making the sinusoidal wave, I would try to bend the flattened tubing over a 1-2" piece of metal pipe. This would take some practice.

Another thought would be to build a manifold with multiple connections so that several of these sections could be used in parallel. Say, 1port to 4. The increased internal volume would help to shorten the CFC. Of course, this would require a wider section of PVC pipe, say 6-8" in diameter.

 

[blacklab]

I completely agree JMD... comments like "who cares" kind of negate my entire career...

didn't mean to tip over your apple cart, sally.

 

[JMD87]

didn't mean to tip over your apple cart, sally.

Please repost in the cider forum

 

[Anthony_Lopez]

didn't mean to tip over your apple cart, sally.

I love the ignorant, uninformed comments you find on the internet... Damn Al Gore for inventing it in the first place...

If you have anything worth while to post, this is a great discussion we have going on here. For those of you that are happy with what you have, I think thats great. My CFC is working great for me as well. No need to rain on someone elses "parade"

 

[Ridemywideglide]

I kindly disagree. That's like saying we can't make our automobiles more efficient without using a different engine. Cars have become so efficient over the past 20 years, and it's because we keep trying to improve an existing design.

I'd have to kindly disagree with you too.. My first car, 1980 citation, would get 27mpg. Now a 2009 corsica with the same motor (3.0 V6) get 27mpg...??
Where's the benefit of 28 years of R&D? Cars are getting no better mileage now than they were in the 80's, it just costs more so we think about it more.

As to the chiller (CFC or not) You can only get as cold as the source water no matter what design or how long or how many tubes you run it through.

 

[JMD87]

I'd have to kindly disagree with you too.. My first car, 1980 citation, would get 27mpg. Now a 2009 corsica with the same motor (3.0 V6) get 27mpg...??
Where's the benefit of 28 years of R&D? Cars are getting no better mileage now than they were in the 80's, it just costs more so we think about it more.

As to the chiller (CFC or not) You can only get as cold as the source water no matter what design or how long or how many tubes you run it through.

Please read the prior posts, the discussion is not whether you can "magically" cool water to below the temperature of the source, it's how you can cool it to that temperature more efficiently.

If your numbers are correct, could you also tell me the Horsepower/torque for both models? I have a hunch that the 2009 corsica has a bit more power.

The car is one example, if you'd rather have a closed mind about these types of things, then go for it. I for one would rather improve than conform.