CFC questions

[JoshuaWhite5522]

I'm about to make a copper in copper CFC, and I'm wondering a few things

1. I'm using 1/2" for the inner tube, should I use 3/4" or 1" for the outer tube? It's is a good deal more to get the 1" but I'll spring for it it the increases size and water volume that goes with it will make the difference.

2. What techniques have you guys used to keep the copper from kinking? I've heard of sand, and water. Any other tips you folks have?


I thought I remember seeing a thread on how to make a copper in copper counter flow chiller. Does any one know which thread I'm talk about. I tried using the search function but to no avail.

 

[phoenixs4r]

Why? May I ask? Seems like a waste of money. If your going for bling factor then the 1" copper would be best, best of luck bending it though.

 

[JoshuaWhite5522]

I guess it's part bling, part durability. I've heard some people have had issues with the copping in garden hose, where the hose would melt.

 

[lud]

I made mine with 1"....I was only able to get it into about an 20" diameter.

 

[outside92129]

i used 1" PVC as the outer tubing and also wound a copper wire around the inner tube. PVC has a higher melting point than hot wort so it's not a problem. Lot cheaper too. I have some 3/4" PVC tubing, you can have it for free (just pay for shipping). PM if interested.

 

[evandena]

Get a good rubber hose that is made for hot water.

 

[JoshuaWhite5522]

I made mine with 1"....I was only able to get it into about an 20" diameter.

thats fine I don't need a super tight coil, what is the over all lenght you went with?

 

[thelorax121]

I am thinking about making the same kind of thing, here are some of the specs that I have worked up:

7/8 OUTER TUBE 1/2 INNER TUBE

AREA

7/8 ID = .4838^2
1/2 OD = .1963^2
1/2 ID = .1492^2

WATER FLOW AREA (7/8 ID to 1/2 OD)

.4838 - .1963 = .2875

COOLANT TO WORT AREA

.2875/.1492 = 1.92

VOLUME OF COOLANT

.015 gal x lenght of chiller (ft)


Compared to the specs courtesy of BobbyM:

CFC Configuration #1 3/8" OD Copper in 5/8" Hose
Wort Flow Cross Sectional Area 0.078
Coolant Flow Cross Sectional Area 0.196
Coolant to Wort Ratio 2.5

CFC Configuration #2 1/2" OD Copper in 5/8" Hose
Wort Flow Cross Sectional Area 0.149
Coolant Flow Cross Sectional Area 0.110
Coolant to Wort Ratio 0.7

CFC Configuration #3 1/2" OD Copper in 3/4" Hose
Wort Flow Cross Sectional Area 0.149
Coolant Flow Cross Sectional Area 0.245
Coolant to Wort Ratio 1.6

My design using 7/8 tubing is closer to the most common configuration of 3/8 and 5/8 tubing and gets me a higher flow rate. Also since the outer tubing is less than 1", i should be able to get a slightly smaller footprint, and should cost a bit less. Since the tubing is usually sold in coils of minimum 25ft, I figure that I can make the chiller a little longer rather than buy the same length of more expensive tube. Also, I will be soldering a spiral of 10 or 8 ga solid copper wire to the outside of the inner tube to create a turbulent flow for the coolant.

If you do got through with this build, please post up your process/results so I can see what to expect

 

[lud]

thats fine I don't need a super tight coil, what is the over all lenght you went with?

Mine's 25'.....