# Double jacket tank sizing

1. Feb 16, 2015

### john11

Hello,

I am trying to design a double jacketed tank for brewing beer. Heating rate rewuired 0.5-1 C/min. Inside capacity of 300-400 liter liquid at ~1.05 d + grain, tank capacity of 600 liter. I can not find a proper calculation for a minimum jacket surface area required for this aplication. I nead to heat all this to ~65C using hot water in the jacket. Also the material of the tank is stainless steel 304.
I will be very thankfull for help with the calculations, preffered metric system. Or at least refference to a relevant equations.
Thank you

2. Feb 17, 2015

### billy_joule

There is no minimum jacket area. The smaller the jacket the greater the temp. Difference is required. At some point the limits of engineering materials will be reached. In other words, you need to define your problem more clearly. What is the temp of the heating fluid?

3. Feb 18, 2015

### john11

Right. The heating liquid will be water at temperature as close as possible to the temperature I want to reach inside the tank mainly around 65C. This to avoid hot spots near the jacket although it will be stirred slowly.

4. Feb 18, 2015

### billy_joule

You may want to rethink your water temp. Heat transfer is proportional to temp difference so as the booze approaches the target temp the heating rate will tend to zero.

5. Feb 18, 2015

### john11

You are right again. That's why I said as close as possible. I am aware that if for example I will want to bring the temperature to 65C I will have to heat the jacket to 67-68 and thats fine. But i would like to stay in the range of 3-5C above the targeted temperature and not to heat the jacket with boiling water.