View Full Version : capacity calculation
steve thailand
22-10-2010, 02:36 AM
hi, does anyone know what cooling capacity i need to cool a liquid (beer in my case) from 10degC to 2degC if the flow rate is 10liters/minute?
we are using a heat exchanger to cool the beer in line as it goes to the filling machine. i need to buy a chiller to drive the heat exchanger and need to know the capacity for it.
thanks, steve
nike123
22-10-2010, 07:55 AM
To cool that beer from 10°-2°C with that flow, you need cca 6kW/h energy removed from beer.
Q=m*c*(T2-T1)
Q= Energy in Wh
m= mass (cca 600kg in one hour)
c=specific heat capacity of beer (water) (cca 1,16 Wh/(kg*K))
T2-T1= temperature diferential (in your case 10°C-2°C=8K)
Capacity of chiller than would be cca 6kW.
@Steve. If you are in Thailand, pm me & I'll give you a useful falang RHVAC manufacturer to talk to.
steve thailand
23-10-2010, 09:18 AM
thanks, so i have another idea. it turns out a chiller and heat exchanger is a bit outside of my budget right now, basically like here to the moon outside my budget so i have another idea.
i have a plastic ice chest, i plan to fill it with ice and water, so water temp about 1-2degC.
i will make a stainless steel box (heat exchanger) , 40cm high, 80cm long, 2-3mm wide (inside). i will drill many 1/2" holes between the two walls and weld 1/2" stainless tube through. so this is my heat exchanger, surface area about 0.5m3, liquid thickness 2mm.
beer comes in at the bottom corner and out the top diagonally opposite corner. flow rate is the same as my original post, 20L/min and beer temp going in is about 8degC.
what temperature drop can i expect to get in this setup? I am aiming to get down to about 3-4 degrees so i wonder, will one of these heat exchangers do it or will i need a few?
by the way, i know i will need to replace the ice a lot as it melts. that's ok, large ice blocks here are quite cheap and i can use the melt water for something else in the bottle filling process (bottle washer/chiller).
thanks again, steve
nike123
23-10-2010, 11:26 AM
In original post you have 10/l min of beer. Now it is 20. Which is correct?
Get a PHE from AlfaLaval, in BKK.
Yuri B.
24-10-2010, 08:40 AM
beer comes in at the bottom corner and out the top diagonally opposite corner.
For best heat transfer it should flow the other way - from up to down.
steve thailand
25-10-2010, 01:39 AM
In original post you have 10/l min of beer. Now it is 20. Which is correct?
my mistake on original post, it is 20L/min
what is a PHE? i'll look into it
moving the beer from bottom to top makes it easier to bleed air from the system on startup i think
thanks
steve thailand
25-10-2010, 01:42 AM
Get a PHE from AlfaLaval, in BKK.
oh, Plate Heat Exchanger
i will when i have money, for now i need to make up my own using ice as a coolant
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