Author Topic: Cold plate in the fridge  (Read 403 times)

Offline MNWayne

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Cold plate in the fridge
« on: November 23, 2018, 04:13:55 AM »
So I'm batting around an idea. Rather than committing an entire mini fridge to a kegerator. Could a cold plate inside the kitchen refrigerator provide enough cooling for an occasional pint drawn from a keg in the neighboring cabinet?

Offline KellerBrauer

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Re: Cold plate in the fridge
« Reply #1 on: November 23, 2018, 02:02:06 PM »
My gut response is to say No.  the refrigerator section of a typical household refrigerator runs at about 38-40 degrees which is fine for drawing a cold beer.  However, the line length you would need to get from the fridge to your faucet in another cabinet would first, be at room temperature. Which means you would start drawing beer at 68-72 degrees or warmer.  Sure, that starter beer can be dumped, but that’s a lot of waste.

Second, the beer would loose much of its cooling in the line from the fridge to the faucet.  So, if the beer in the fridge is at 38 degrees, it may be at 45 degrees (or higher) by the time it gets to your glass unless you do a real good job insulating that line.  So this idea is really not practical.

All that said, if you can mount your faucets on the fridge itself, problem solved and mission accomplished!
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Offline Robert

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Re: Cold plate in the fridge
« Reply #2 on: November 23, 2018, 03:57:22 PM »
So what you're talking about is basically the same idea as a jockey box.  It seems plausible to me that this might be made to work,  but the fundamental problem I see is that the refrigerator is too warm and the freezer is too cold for locating the heat exchanger and lines.  You might need a dedicated piece of equipment to serve as a permanently chilled jockey box.  Don't know what that would be.
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Offline MNWayne

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Re: Cold plate in the fridge
« Reply #3 on: November 24, 2018, 02:36:12 AM »
Sorry for the confusion, the keg would reside in the cabinet and the tap mounted to the side of fridge. The freezer would of course be too cold, so the plate must be in the refrigerator section. So it's plausible that a single beer could be drawn cold enough for enjoyment? My only jockey box experience is with a coil, I'm not aware of the cooling capability of an aluminum plate. I guess the real question is, can a plate chill 68 degree beer to serving temp using a 35 degree heat sink?

Offline Robert

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Re: Cold plate in the fridge
« Reply #4 on: November 24, 2018, 03:22:40 AM »
Since your heat sink is very close to desired serving temperature,  I'd say no, intuitively.  It's about the capacity for removing heat from that sink.  Jockey boxes provide much more surface for exchange (long coil) at a much greater differential (ice bath.)  Important  to note here is that the thermal mass of the ice bath is very different from that of the air in your fridge as you are proposing to use.  The air in the  fridge just won't be able to remove heat from the plate, or any other exchanger, fast enough.   But I think this is now above my pay grade.  Tapping out.   Engineers?
Rob Stein
Akron, Ohio

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Offline Richard

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Re: Cold plate in the fridge
« Reply #5 on: November 24, 2018, 05:21:05 AM »
I am not very familiar with jockey boxes or cold plates in this context, but my instinct tells me the same as Robert. The thermal mass seems inadequate and air contact is a very poor way to cool something.
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Offline KellerBrauer

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Re: Cold plate in the fridge
« Reply #6 on: November 24, 2018, 01:42:57 PM »
Now I understand your question, thanks for the clarification.  I am also not familiar with a cold plate.  But I think we can view this the same way we view a refrigerator with an external water dispenser.  The water enters the fridge warm and comes out cold.  Simple, right?

Inside the fridge is actually about 30 feet of plastic tubing coiled up and laying on the bottom, typically under the fruit and vegetables drawers.  Now, when you draw water, it’s cold, but not as cold as one would like their beer.  That’s because the coil is located on the bottom of the fridge.  If that coil were located on the top, where you would normally keep a bottle of your favorite brew, than the water would exit the fright very cold, like that cold bottle of beer.

So, the answer to your question: YES, It will work providing the coil is located at the top of the fridge and your fridge thermostat is set to about 36-38 degrees.  Note, I say “coil”.  Again, I’m not familiar with a cold plate nor the thermal conductivity of this product.

Now, the length of your coil you use would be relative to the quantity of beer you wish to draw before allowing time for fresh (warm) beer to cool.
« Last Edit: November 24, 2018, 01:47:09 PM by KellerBrauer »
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Offline MNWayne

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Re: Cold plate in the fridge
« Reply #7 on: November 25, 2018, 04:27:35 PM »
Thank you all for your thoughts. I was skeptical about this. I will post a plea for ideas on a separate thread.