Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Ask HN: DIY ice bath equation for water cooling

news.ycombinator.com

Post reply on HN
Print view View original

1–10 of 31 posts

Ask HN: DIY ice bath equation for water cooling

#1

Post by fishbone »

I am making an DIY ice bath at home. I have about 40 gallons of water in a tub and a chest freezer. Prior to cooling, the water is typically around 70 degrees F. I am thinking about getting a coil and running water lines through the chest freezer to circulate the water, but I don’t want to waste money and cut holes in the freezer if it’s not going to work. I would like to cool the water to as close to 40 degrees F as possible.

This 25’ coil would easily fit in the freezer.

https://www.northernbrewer.com/products/copperhead-immersion-wort-chiller?variant=30232177049644&gclid=CjwKCAjw3ueiBhBmEiwA4BhspOWqTsk7pH3VvEQq6-HeDgUodqlCS51VMeE3TM28-Ak07fVyHvHotxoCmb4QAvD_BwE

I would appreciate any advice the HN community has to offer!

Re: Ask HN: DIY ice bath equation for water cooling

#4

Post by OJFord »

40 US gallons ~= 150l, seems (even a bit bigger to accommodate the different shape of the tub to fit in) perfectly within the realms of chest freezers, is getting a different freezer instead out of the question, i.e. to simply put the tub in the freezer?

If you do want to do it the way you suggest, probably better to run a closed loop as a heat exchanger in the tub to be cooled, rather than circulating that fluid directly. I'd have thought you'd also want the coil inside freezer to be submersed in something, even if just another tub of water (block of ice) to improve transfer, but that's just intuition/guesswork, not sure about that.

Re: Ask HN: DIY ice bath equation for water cooling

#5

Post by anderiv »

nickhalfasleep wrote: post #2

Freezer compressors are sized for simply keeping the contents cold of their well insulated box. Trying to run an external load will likely overload it’s capacity.

Agreed. And even if the motor could take the load, the OP’s 25’ coil will be nowhere near enough. Think 4x that much in length and add fins/heat sink to increase thermal transfer.

Re: Ask HN: DIY ice bath equation for water cooling

#7

Post by Y_Y »

Gallons, inches, Fahrenheit? I was willing to do some quick calculations, but irrational cultural dogma prevents me from looking up the appropriate conversions.

In any event what's missing is the environment. Is this a bath tub? Is it in a sealed room? What's the ambient temperature?

Re: Ask HN: DIY ice bath equation for water cooling

#8

Post by aruametello »

in short: the tub idea would work but feels a bit cubersome.

a different approach to possibility the same target results would be to use "Termoeletric cooling" (https://en.wikipedia.org/wiki/Thermoelectric_cooling) often described as TEC/peltier to cold down a surface (metal surface in your loop?) to bellow air temperature.

the short description: it is a device has a hot side that will be kept X degrees above the cold side, so if the X of your tec is "50 ish", if you cool the hot side to 60c, the cold side will be 10c. (its often easy to go bellow 0c)

now the bad news... they are VERY power inefficient, you might spend 200w 12v DC on it to pull of 100w of heat on the cold side, so not for the "power consumption conscious" crowd. those are handy to create a cold water drinking fountain because they can be toggled quickly. (perhalps just run it when needed?)

Re: Ask HN: DIY ice bath equation for water cooling

#9

Post by wtk »

A bit of an offtopic: lucky (unlucky) to live in a country where winter means temperature around 0 (down to -5/-8 C) I simply put a 210L rainwater collector on my balcony. Best thing ever to be able to take an ice dip from comfort of my home - with an airbike for warm-ups, and a warm shower. I'm not a giant, so 210L is enough to duck and get covered to level of my shoulders. Below €20 and zero effect on electricity bill :)

Re: Ask HN: DIY ice bath equation for water cooling

#10

Post by TeMPOraL »

Y_Y wrote: post #7

Gallons, inches, Fahrenheit? I was willing to do some quick calculations, but irrational cultural dogma prevents me from looking up the appropriate conversions. In any event what's missing is the environment. Is this a bath tub? Is it in a sealed room? What's the ambient temperature?

> Gallons, inches, Fahrenheit? I was willing to do some quick calculations, but irrational cultural dogma prevents me from looking up the appropriate conversions.

I normally don't post GPT responses, but this case warrants exception. Here is the OP's question translated into something understandable by the rest of the planet, along with something resembling an answer.

https://cloud.typingmind.com/share/c930c7fd-f609-40a5-9ebf-a... (GPT-4)

Post reply on HN