"crash" cooling

[aswissbrewer]

glycol temperature

Thanks for the hints!
The compressor doesn't run all the time while I am cooling the tank and seems to handle the heat ok. So the problem must be tank side.

As to the temperature of the gycol line - that's a little tricky to measure. I had to unscrew the lines and measure the temp as the glycol flowed into a bucket. The glycol flows out with a good pressure so I guess it isn't blocked. In fact that's what made the whole process b----- tricky .

Example temps as far as I can tell:
Line into jacket temp: 2.5 - 3 C
Line out of jacket 3.5 -4 C
Glycol in chiller 1.0 - 1.5 C
Beer temp 7 C

I raised the gycol temp up over 0 C in order to rule out ice formation. (At least thats what I figured). No real difference.

What I do notice, is that the temperature of the beer comes down slowly and then if I do cut the cooling off with the thermostat the beer continues to cool and "overshoots" so to say. Ice ?

The tank thermometer is low down in the tank and I am also thinking that the settling yeast (some does settle) might be disguising the temperature a little? Possible ?

Be glad to hear from you guys again.

Steve

[Brew49411]

You need to check your gravity before you crash..... Don't just guess cause sometimes you'll get burned. When your within about 1 degree from your target crash that baby from 18 right to 4. Thats how I roll!

[jimvgjr]

The compressor doesn't run all the time while I am cooling the tank and seems to handle the heat ok. So the problem must be tank side.

This is definitely a good indicator, it could also be the result of lack of flow through the jacket- which would limit the amount of heat being exchanged.

As to the temperature of the gycol line - that's a little tricky to measure. I had to unscrew the lines and measure the temp as the glycol flowed into a bucket.

This is always a challenge to get good temperature readings, it is best however to keep the piping connected. When you removed the outlet pipe and let the outlet flow into a bucket, you likely reduced the line restriction and saw a greater flow than if the outlet pipe was connected to the fermenter- therefore your data might not reflect your normal operating TD across this jacket. Does that make sense??

There are inexpensive electric thermometers with small sensors that you can affix to the outside of the pipe, or the outside of the stainless fitting on our tank inlet and outlet (place some insulation on over these sensors). With a sensor on both sides of the jacket, you can monitor these temperatures at various times during the day to get a better idea of the TD across the jacket.

What I do notice, is that the temperature of the beer comes down slowly and then if I do cut the cooling off with the thermostat the beer continues to cool and "overshoots" so to say. Ice ?

The tank thermometer is low down in the tank and I am also thinking that the settling yeast (some does settle) might be disguising the temperature a little? Possible ?
Steve

I am not sure on this one, guess you should make sure that your solenoid is shutting off.

Good luck Steve!

Jim

[aswissbrewer]

Post Script

sometimes, depending on your parameters (glycol temp, jacket area, etc) you can over do it. recently i worked with some 200HL tanks and they were taking more than two days to get to 4 degC. i found that when we reduced the glycol flow to these tanks that the cooling was actually more effective - ended up getting from 22degC to 4degC in 24hrs (so there was some icing on the jackets causing lack of heat transfer).

alex

Been having a few problems with my cooling system lately. Amoung other things a solenoid burnt out on me. This is one that stays in the open position when no power is getting to it.

This meant that the line was constantly open and subsequently when a thermostat on another tank cut in, coolant flowed through this solenoid as well. The tank was subject to constant but intermittent cooling.

What I noticed is that the beer temperature sank at a higher rate than if I had "crashed". It seems that the on-off coolant flow was more efficient.

Right on Alex T !

[Ted Briggs]

Two things to think about for effecient heat transfer:
--slower is better- throttle back the out flow for longer contact time. Make sure you dont exceed the tanks psi rating though.
--Less glycol is better- glycol keeps the water from freazing but reduces its heat transfer ablity.
Ditto on the point of selective harvesting of yeast. Try to crop your yeast early in the cycle to get faster dropping yeast. Basicaly this is genetic manipulation by selection. Though fast dropping yeast will probably be less attenuative!.....