#### argon

##### firmitas, utilitas, venustas

- Joined
- 8/5/09

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I wanted to understand (or at least have an estimation of) how long it would take to chill the entire volume to my desired temperature based on the variables of the following:

- Recirculation flow rate

- Wort Out Temperature

- Chiller Out Temperature

- Chiller Water Temperature

- Wort Volume

A couple of knowns;

1. My ground water through the chiller gets my boiling wort down to 27C

2. To achieve the most efficient cooling i run the wort through the chiller at 3L/min

So i wrote a couple of little equations and plugged them into excel. This then generates a dynamic schedule that tells me how long it would take to get the entire volume of wort to my chiller water temp.

T

_{F1}= Temp in Kettle @ flameout

T

_{F2}= Temp in Kettle after each chilled addition

T

_{1}= Temp

T

_{2}= Temp

V

_{1}= Hot wort out of kettle

V

_{2}= Chilled Wort out of chiller

T

_{F1}= [V

_{1}/V

_{F}x (T

_{1}-T

_{2})] + T

_{2}which changes to;

T

_{F2}= [V

_{1}/V

_{F}x (T

_{F1}-T

_{2})] + T

_{2}after first chilled addition

In my circumstance, with my constants, the estimated time it takes to drop 23L of the wort from boiling to approx 27C by way of the recircing chiller is

__approx 4 mins__.

Wheras the 'passive' chiller, where the hot portion of the wort remains in the kettle, the estimated time it takes to drop the 23L of wort from boiling to approx 27C is

__approx 8 mins__

In simplistic terms, what is happening is, that instead of chilling wort that is at a constant temp (ie sitting just below boiling), the recircing chiller is chilling wort that is actively dropping. Thereby, creating a very fast efficient chiller.

So i'm yet to test this and i expect that i'll need to stir the kettle whilst chilling to make sure that the chilled portion of wort is properly homogeneous throughout the hot portion.

I still think, in practice, it will take a little longer due to equipment heat and ambient temperature fluctuations, but it should give me a broad estimation of how long it may take. Next time i get some free time i'll do a hot water run and log actual times and temps and see how close the calculator is in application.

I've attached the excel sheet for anyone that thinks it may be interesting to have a look at. Everything is editable, just change the red cells to see their effects in regards to time and temp. Feedback on how it may be improved (or why it may not work) is appreciated. Hope someone finds it useful or interesting.

View attachment Recircing_Plate_Chiller_Calculations.xls