Cooling coil positioning and flow

[richc]

I've just got a single coil immersion wort cooler and was wondering how to set it up and plumb it in.

Question 1. Where should it be positioned in the boiler?

Obviously near the center but my logic says it should be just below the liquids surface because this is where the hottest wort will be, cooling here will drive convection and the higher temperature differential will cool the wort quicker.

Question 2. For a single coil should the water enter at the top of the coil or the bottom?

Following similar logic to that above my immediate thought is what the water should enter at the top for the greatest temperature difference.

So is my ex physicists logic right or have I made a basic mistake somewhere :wha:

 

[evanvine]

When I've come across ICs they have not be been permanent fixtures, indeed they're used to swirl the wort in the boiler to get faster, more even cooling.
When used in this way I don't see it matters which way the water flows.
Personally I use a CFC, which cools 23ltrs down to pitching temp in 11 mins.

 

[Good Ed]

Hi Rich, the IC I have hangs from the top of my boiler using a length of plastic pipe, I don't have a pic I'm afraid, but if you trawl through the Brewday posts you'll probably see one. Make sure your coil is clean and put it into the boiler 10-15mins before the end of the boil to sanitise it. Although on my last brew I just sanitised it in the normal way because I found that putting it in before the end of the boil resulted in all the hops in the boiler floating inside the coil in a clump.

Also the cold feed comes in to the top coil with the hot water out from the bottom. I find that you don't need much flow of water, but you will get used to it. I take the wort down to about 28C and by the time you've drained it off to the FV and aerated, it is about 22C. Takes mine about 20-25mins. You can also give the wort a gentle stir to circulate to help the cooling.

Good luck :

 

[graysalchemy]

Adjust your flow of water so that you get the highest temp at the outflow you can. This is the most efficient use of water and you can collect a few buckets worth to do your washing up with. Also don't let it flow onto plants or the grass if you are tempted to recycle your water in the summer as it will scorch them. :nono: :nono:

 

[Hawks]

I thought cold should go to the bottom and hot out the top... :?

 

[Good Ed]

I think the logic of the cold going in the top is that it enters the wort at its coldest and travels through the coil to the bottom, whereas if it went to the bottom of the coil first the water would have already heated up travelling from the top of the wort to the bottom before going through the coil; I always stand to be corrected though :)

 

[Springer]

I go with E. on this, doesn't matter much. If you are agitating the wort with the coil, which you need to do or it will get the wort close to it very cold and not be very efficient, the temperature difference within the wort should then be pretty constant throughout :?
Other more learned members may have other views

 

[richc]

Adjust your flow of water so that you get the highest temp at the outflow you can. This is the most efficient use of water.

Isn't this also the least efficient cooling?

 

[richc]

I think the logic of the cold going in the top is that it enters the wort at its coldest and travels through the coil to the bottom, whereas if it went to the bottom of the coil first the water would have already heated up travelling from the top of the wort to the bottom before going through the coil; I always stand to be corrected though :)

Wouldn't it be still cooling the wort as it traveled from top to bottom?

 

[robsan77]

Adjust your flow of water so that you get the highest temp at the outflow you can. This is the most efficient use of water.

Isn't this also the least efficient cooling?

If you can get the maximum flow of water you can with the highest temp water coming out then it is as efficient as it will get. Pumping more water through wont cool it any faster, it will only use more water. only using a bigger coil will cool it faster.

 

[robsan77]

I think the logic of the cold going in the top is that it enters the wort at its coldest and travels through the coil to the bottom, whereas if it went to the bottom of the coil first the water would have already heated up travelling from the top of the wort to the bottom before going through the coil; I always stand to be corrected though :)

Wouldn't it be still cooling the wort as it traveled from top to bottom?

exactly. It doesnt really matter which end it goes in as the others have said. What you want is to use the coil as efficiently as possible. too slow a water flow and the water will be fully heated way before its finished its journey through the coil. Too fast and it wont heat up fully, coming out cooler and wasting water. What you need to do use every inch of the copper pipe so that the water is only fully heated just before it comes out the end.

 

[richc]

Adjust your flow of water so that you get the highest temp at the outflow you can. This is the most efficient use of water.

Isn't this also the least efficient cooling?

If you can get the maximum flow of water you can with the highest temp water coming out then it is as efficient as it will get. Pumping more water through wont cool it any faster, it will only use more water. only using a bigger coil will cool it faster.

Yes, if the amount of water you use is important to you. If the amount of water you use isn't important to you then I would have thought your flow rate should be as fast as possible. This would give the highest difference in temperature between the coil and the wort and therefore the greatest heat flow?

 

[Good Ed]

I think it's all about heat transference, not flow :wha:

 

[evanvine]

This may not be pertinent to an IC cooler.
I use a CFC, and in the fisrt days put a temperature probe into the outlet.
The faster I ran the water through the chiller the cooler the wort got!
It never reached a point where increasing the flow didn't increase the cooling effect.

 

[richc]

My understanding is that the only thing that matters is the difference in temperature between the outside of the pipe and the wort touching it. Therefore the cooler you can make the pipe the more heat will be transferred out of the wort.

Apologies for this bit, I'm getting flashbacks to being at university (many years ago) ;-)

I think the tricky thing here is that temperature and heat are not the same thing. Heat is energy whereas temperature is a measure of heat per unit volume. If you put the same amount of heat into a larger volume of water it's temperature will end up lower. Therefore (told you this was the science bit ), the temperature of the water coming out of a cooling coil isn't a good measure of the amount of heat being extracted from the wort.

 

[evanvine]

I think the tricky thing here is that temperature and heat are not the same thing. Heat is energy whereas temperature is a measure of heat per unit volume. If you put the same amount of heat into a larger volume of water it's temperature will end up lower. Therefore (told you this was the science bit ), the temperature of the water coming out of a cooling coil isn't a good measure of the amount of heat being extracted from the wort.

I quite agree, heat is a quantity and temperature is a level!

 

[Vossy1]

Firstly, I am no expert, but I've had some advice from folk that are....IIRC

There's one limiting factor and that's the pipe itself, be it IC, cfc, or plates in a plate chiller.
You are working with a set surface area, that of the pipe or plate, and as such it's finite.
The most efficient heat exchange occurs when there is the biggest difference between coolant and product to be cooled. Once you reach a certain flow rate through the pipe, with a static (ish) wort outside the pipe, and more importantly a linear flow through the pipe, there is no gain in increasing the flow rate.
You can increase the surface area in a cfc or on a IC by using convoluted copper tubing. This ensures more of the coolant/wort is in contact with the surface area of the heat exchange surface, thus giving better heat exchange, but more importantly it creates turbulent flow of the coolant/product, meaning it is more efficient. In the case of a IC you wouldn't notice much difference unless you whirlpooled.
Plate chillers have a herring bone design (primarily) to increase the surface area, but also to create turbulent flow of the coolant and product, again thus increasing efficiency.

As convoluted copper tubing is VERY expensive it's not really used for IC's/cfc's.
To make your IC as efficient as possible you should whirlpool the wort.

On a personal note, I've experimented with both IC's and cfc's. My cfc (IIRC) used to be one length at 15m and it worked o.k, taking the wort to pitching temps with a good flow of water as coolant. I often wondered if there was a point in the cfc where the heat exchange became minimal, ie, how much of that 15m wasn't really being used. I cut the outer coolant hose in half meaning the top half of the cfc had a supply straight from the water tap, and the bottom half had it's own supply. The result was the same cooling using a lot less coolant, trickle v torrent.

I also made a 4 coil IC, each coil having it's own separate feed. I didn't really see much benefit to this, but then again I didn't whirlpool the wort, as I'm paranoid about things flying/falling into it :lol:

Get your IC used rich, try coolant both ways and let us know what your results are, either way you'll get great beer :thumb:

 

[evanvine]

Firstly, I am no expert, but I've had some advice from folk that are....

Bloody hell Vossy, and you said you don't give the Forum enough time!
That was one of the most concise and informative post's I've read on any Forum. :clap:
Just keep those coming every once in a while.........THBF will be all the richer for it

 

[Good Ed]

Good stuff Vossy :thumb: and rich I'm sure your beer will taste great whatever you do