Wort Chiller Just Ain't Chillin

[danestead]

Um....er...no...would depend on your volumes, surface areas, length etc

You would get a different result if you used different sized tube.

The longer/bigger you counter flow chiller the more heat you can transferr

Yep you are right, I'm just retarded and should just keep quiet. I know how it all works, I am just hopeless at explaining and am missing bits here and there

 

[Burt de Ernie]

The temperature of the outlet water can be monitored as long as the temperature of the wort is being monitored at the same time and the outlet temperature has to be lower than that of the wort otherwise the heat from the outlet will be heating the temperature of the wort.

So, by this statement it sounds like you are saying you can heat the wort using a chiller and cold water??

I must be reading this wrong.....what is it? Cold fusion?

 

[Burt de Ernie]

In reference to this, if it was a counterflow copper coil chiller or counterflow plate chiller, I'm thinking it would be possible to have hotter water coming out of the outlet of the chilling water, than the outlet of your wort going into the fermenter. I haven't tested this, however Im thinking it's possible.

Thoughts?

 

[Back Yard Brewer]

Is it a counterflow or straight immersion?? Its all about flow rate. Too fast and the cooling water wont be in contact with the hot stuff for long enough to absorb the heat. Stainless is great for cleanliness but not the worlds greatest heat conductor. Copper is better for heat transfer. Slow your flow and give that a crack.

Beers,

My chiller of choice. Expensive but I swear by it. http://wortwizard.com/cart/ChillZilla-Chiller

 

[wide eyed and legless]

So, by this statement it sounds like you are saying you can heat the wort using a chiller and cold water??

I must be reading this wrong.....what is it? Cold fusion?

I am referring to a copper immersion chiller, cold water goes in and as the heat exchange takes place the water coming out is hot, when travelling through to slow the cooling will heat up to the same temp as the wort, therefore keeping the wort at a high temp speeding up the water just enough to have the water coming out a few degrees less than the temp of the wort would be ideal.

 

[TheWiggman]

Not necessarily wideeyed. Many in this thread are focussed on the temp of cooling water coming out. Think of it the other way around - the temp of the coil in the wort.
Because really, what are we looking at here? Trying to heat the water (eg. HERMS) or trying to cool the wort?

Assume tap water is 20°C.
If I dipped a big coil in the wort that maintained a constant temp of, say, 20°C across the entire coil then the wort will be exposed to a big thing which is a lot cooler than the wort. Ignoring the "doesn't have time to transfer heat" argument (which is false) just think what's going to happen if you have a big coil in the wort that stays at 20°C. The liquid contacting it will be 20°C, and thus the more it's moved around the quicker it will chill the whole thing because it's not relying on conduction.

If the liquid is running absolutely flat out i.e. at theoretical limits the IN temp of the water will be 20°C and the OUT temp will be 19.99°C. The majority of the coil will be very cold. More exposure to cold = quicker chilling.
If the cooling liquid is slowed so that you have OUT at 80°C immediately after flameout then there will be a big temperature gradient from 20 - 80°C across the length of the coil, because the wort is heating the cooling water. Thus less exposure to cold = slower chilling.

Again, ignore the cooling water and just think about what the liquid in the kettle is seeing - if it's exposed to a large, cold surface then it will chill. The colder and greater the surface area, the faster it will reach that temp.

 

[wide eyed and legless]

heat exchanger, any of several devices that transfer heat from a hot to a cold fluid. In many engineering applications it is desirable to increase the temperature of one fluid while coolinganother.

 

[Goose]

Speeding up the water just enough to have the water coming out a few degrees less than the temp of the wort would be ideal.

Ideal for the hottest exit cooling water you can achieve. Ideal to save water too, and great if you need hot water for a shower or washing up. But not necessarily good for cooling your wort as quickly as possible

 

[TheWiggman]

Exposing something cold to something hot will result in an exchange of heat (or more to the point, energy). It is not desirable to increase the temp of the cooling fluid, it's desirable to decrease the temp of the wort.
If water's running through the coil an exhange of energy will take place no matter what - didn't think I needed to say that. As I and others have said earlier, the more turbulent the water is, the more effective the heat transfer.

Stop thinking about what's happening to the cooling water, think about what the wort is being exposed to first. That should tell you why you don't want hot water coming out of the coil (assuming you have good flow outside the coil).

 

[wide eyed and legless]

They are called heat exchangers for a reason, heat is exchanged from one fluid to another, in this case the wort to the cooling fluid, the outlet of the cooling water temperature is significant, if it is hot then an exchange of heat is taking place,and rapidly taking heat away from the wort.

http://www.engineersedge.com/heat_transfer/parallel_counter_flow_designs.htm

 

[Ducatiboy stu]

But if it is hot comming out, then it cant transferr as much heat from the hot wort. If the the chiller water is heating up in the first section of the coil, at the chiller input/ wort output, and remains hot all the way to the other then it cant transferr as much heat as the chill water is hot for the remaining section. If the water coming out of the chiller at the wort input end is cold then it will start to chill the wort right at the start instead at the other end. If the wort hits cold water at the input of the chiller then its going to be able to transferr more heat along its path to the output because its in contact with cold water for longer.

 

[Online Brewing Supplies]

All my experience with chilling has been with plate chillers both commercial and at home.
My point from the beginning is there is a sweet spot (balance point) when chilling where you are getting maximum efficiency from your cooling process given a set apparatus..
IE you turn up cold flow it does nothing to increase heat removed from the wort in the chiller, (as shown on an outlet thermo), this is a practical example not theories on paper and after all aren't we looking for the most efficient way to achieve the result ? I know I am.
Nev

 

[TheWiggman]

You're right Nev, there will be a point at which there will be little to no gain. You're saying you're judging this on the wort temperature - THAT'S what matters. With an immersion chiller it's nigh-on impossible to know this point. Textbook examples will give you the same results.

"if it is hot then an exchange of heat is taking place,and rapidly taking heat away from the wort."

http://www.engineersedge.com/heat_transfer/parallel_counter_flow_designs.htm

This statement is incorrect. If the temperature has changed it means an exchange of heat is taking place. It doesn't need to be hot for the many reasons explained before. The link you sent me is for a counterflow which is a different system, but still proves that point. High temp difference = better. If the Tcout on the graph on the right was lower, you'll maintain a high temperature difference which will give you a Thout that is lower.

I think I've reiterated the same point enough - I'm abandoning this thread!

ED: Please disregard any theory and continue to sell the HERMS coils Nev because they work a treat.

 

[Ducatiboy stu]

if it is hot then an exchange of heat is taking place

It has taken place. Once its hot it can no longer transferr anymore heat. Once its hot you need to move it so that more water can exchange heat.

If your not moving the chilling water away from the hot wort it will just heat up and stay hot.

 

[wide eyed and legless]

It has taken place. Once its hot it can no longer transferr anymore heat. Once its hot you need to move it so that more water can exchange heat.

If your not moving the chilling water away from the hot wort it will just heat up and stay hot.

Of course, but the cooling water is not static it is moving through the heat exchanger constantly, picking up the convected heat, I have a copper coil made from 19 mm tube and do as you used to do, my cooling water recirculates from the bottom of 5000 litre water tank and cools the wort down in no time, if as has been said in previous posts the wort is kept moving.
Which method would be the quickest, to keep the coil at a lower temperature by speeding up the water and stirring the wort as Wiggman suggests I don't know, but I was more than happy with the way I was doing it when I was cooling my wort instead of no chilling. Also it would depend on each individual with whatever they are using to cool the wort and if they have a supply of water like a tank or having to use town water.

 

[Goose]

Howdy WEAL,

I am a Goose, so am struggling to see your point. Are you able to state it succinctly please ?

Cheers

 

[wide eyed and legless]

Hi Goose,
Its pretty straight forward,I have, as said above a 19 mm copper coil immersed in the wort, cold water went in and hot water came out, my water is drawn from the bottom of a water tank and the heated water goes back in to the top of the tank, I never measured the temp of the water coming out but it was an efficient way for me to cool the wort effectively.
If the flow of the water is to slow the heat from the wort will not dissipate effectively so the balance has to be found for the equipment the brewer is using as Nev stated.

 

[Burt de Ernie]

I am referring to a copper immersion chiller, cold water goes in and as the heat exchange takes place the water coming out is hot, when travelling through to slow the cooling will heat up to the same temp as the wort, therefore keeping the wort at a high temp speeding up the water just enough to have the water coming out a few degrees less than the temp of the wort would be ideal.

Ok ...I misunderstood however if you want to chill wort fast, the colder the discharge water the quicker the chill.

 

[Burt de Ernie]

They are called heat exchangers for a reason, heat is exchanged from one fluid to another, in this case the wort to the cooling fluid, the outlet of the cooling water temperature is significant, if it is hot then an exchange of heat is taking place,and rapidly taking heat away from the wort.

http://www.engineersedge.com/heat_transfer/parallel_counter_flow_designs.htm

This is poor theory....simple fact is... the cooler the discharge water...the quicker the wort temp will drop.

As previously proved in this thread, the way to get cooler discharge is to increase flow. The result of this is that the wort cooling time will be reduced

 

[wide eyed and legless]

I am on the right tram now, found some very informative articles on some of the American brewing sites, going through Chemo at the moment so the little grey cells aren't working quite so good,apologies to Wiggman, he was right and I was wrong.