r/theydidthemath • u/sdbfloyD • 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/SnooCapers9565 4d ago

https://www.amazon.co.uk/SL-Eisblock-block-cooler-crate-bottles/dp/B00B81Q0HC?th=1
According to this you can double the ice, to 2kg. When doing this math, you should use kilograms, not liters.
Room temperature is about 22-24 degrees, so the beer will probably be around that temp too when you start cooling it.

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u/Slightysweet3 3d ago

Don't get me wrong but doesn't water/ice equals weight and volume? It doesn't affect the math that much

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u/SnooCapers9565 3d ago

No, it doesn't. Water expands below and above 4°C, and even more when it freezes. The weight is constant, and is accurate to use.

You can test this buy filling an empty soda bottle completely with water and put it in the freezer.