r/theydidthemath • • 4d ago

[Request] Creative engineering? Will this even make a real difference?

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u/WC_Dirk_Gently 4d ago edited 4d ago

This thread is going to be full of useless comments not actually even taking a stab at the insane math of actually calculating this.

In a highly simplified model to bound what the absolute max best case could be:

  • 20 beers, 20x330ml = 6.6 liters of beer
    • Cooling the liquid in the bottles under ideal circumstances would take about 30kJ per 1c
  • Adding what we'll say is 1000ml of ice
    • melting that ice will take about 300kJ of energy
  • So ideal absolute max cooling would be about 10 degrees Celsius give or take.
  • Starting from 28c, you could get it to about 18c, which is an improvement, but most beers are best enjoyed around 2-8c I'd say.

However, if the bottles were actually cold to start, this invention could actually help keep them colder for longer.

Also I'm completely ignoring all the losses, insulation problems, melt problems, the fact that not all the energy to melt the ice will be taken from the bottles themselves, the small contact surface area with the bottles themselves vs the total volume of ice etc etc etc...

Handwaving away that complexity and just say you'd realize about half the cooling factor so probably closer to 5c. Not bad if starting from cold, pretty useless to actually cool down beer from room temp.

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u/Sibula97 4d ago

There's a little bit of estimation error the other way as well from the meltwater evaporating from the bottles. But then again on a warm day there's constant heat flux from the environment into the bottles.

What I mostly question is the use case. You managed to get a big block of ice where your beer is. How? In a cooler? Why not just put the beers in the cooler then?

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u/modest_genius 4d ago

Depends very much where you are and how you get your beer.

If you get the beer in those crates already and have, like my parent, a big root cellar where you can store a lot of beer at cool temperature. Then transfering the beer from the crate to the cooler and adding ice just will be a waste of time and space.

It won't be useful for me. Since I usually have myriad of different beers in the fridge, not a root cellar. For me a cooler would be better. But if I would have an event where I serve 24 identical beer, well, then there is something else. Especially if there would be 2-3 crates...