# Help me understand cooling capacity

One thing I’m having trouble with, as someone with no specific science background, is figuring out what size of chiller I actually need and with what KW capacity. I am looking to find a chiller that will keep the jacket on one of my pieces of equipment cold while in operation. The liquid capacity on my jacket is 25L and I’m shooting for a temp of around -60c. Does that mean I need a 25L chiller? At face value it seems that way to me, But I’ve seen 8L chillers that claim 25Lpm circulation… but will it keep temp if the reservoir is smaller than the vessel I’m cooling?

There are a number of factors when calculating a chiller size, or an HVAC system for that matter. It does not necessarily matter the size of the vessel, but how much heat you need to remove. For instance, you can have a small vessel with an internal heat source that needs 3x as much cooling as a vessel twice the size with no heat acting against you that can use a smaller chiller.

You want to figure out how much energy(heat) your “pieces of equipment” are generating, and find a cooler that can keep up to your standards.

Lets say you get a chiller with 2kw of cooling power, and you only need 1kw of cooling power, in theory you wouldn’t even need a large reservoir the chiller would be able to keep up. Same idea goes for circulation, you might not need to circulate so fast if the thermo fluid is keeping your vessel cool. Lots to take in to account.

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Yes. Ok Right now I’m using prechilled ethanol in my jacketed centrifuge. The Ethanol goes in at -60c but after a 10 min agitation and a 10 min spin, what comes out is down to about -20c. This so the solution has to go back in the freezer to chill again. Given that thee freezer takes about 10 hours to bring it back to temp, you can see my problem. I can’t run more than one extraction at -60c a day. The motor is on a separate end from the spindle and basket, so the only real heat created is the friction. And given that the machine is running for a far shorter time than it is capable of, it doesn’t generate much heat. I can’t feel any heat being generated from the motor externally. In retrospect, I know most of my mistakes with my setup, but I’m not really in a position to do an overhaul on my process. So I’d like to start using the jacket with a chiller to keep the internals cool and minimize heat loss.

Hello ,
we defenitely can help you to size the correct chiller. And there are multiple factors to calculate the needed KW. The size and material of your vessel matters , since that goes into the equation of the total masses ( heat removal )
Please e mail me ( georg.kiefer@huber-usa.com

You are chilling the centrifuge with your solvent. One solution is to pull a vacuum on the jacket, which will insulate the internals from your 20C lab. Then prechill the centrifuge with dry ice or liq N2. If you run -60C fluid in the jacket, you end up with a giant snowball in your lab. Which has its own set of problems.

And you noticed that your freezer doesn’t have enough chilling power as well… ethanol has a specific heat capacity. You use that to calculate how much heat you need to remove over your desired timeframe. The size a chiller with at least that capacity.

Math is around here and labeled well.

Try here:

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There is a simple solution to the Probleme:

Call Huber USA 1-800-726-4877

We size and spec the correct chiller for your application. We explain our calculations and have numerous case studies.

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nah, not even the preantepenultimate

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C’est la vie. As far as forum karma goes, I will HAPPILY answer repetitive questions on cooling loads in exchange for everyone tolerating my repetitive questions about how to get the special sauce out of the plant.

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