Thermal Modeling: Predicting Water Temperature in an EPS Box

[Fancy Moses]

Hi all!

I need to figure out a way I can predict the temperature range a small container of water (neglect properties small container and focussing on the water itself) will hold within an insulated expanded polystyrene (EPS) box of a given thickness, over a period of time. We can assume the ambient temperature is constant outside the EPS box. Surrounding the small container of water will be some frozen (~ -20ºC) water packs and some refrigerated (~ 5ºC) water packs that will all fit inside the EPS box. So a 2D cross section would show the layers in this order (outermost to innermost): EPS, Frozen water pack, refrigerated water pack, container of water. All the dimensions would initially be provided. I have some testing to do and this would REALLY save me some time. I haven't done any thermo in a long time so I'm sort of struggling with this one. I'm not looking for anything solved, just the necessary steps required and formulas associated.

Thanks!

 

[nirax]

if outside you have a ice pack+water mixtire, then the temperature of anything that is inside will be held at zero until all the ice melts.

 

[Fancy Moses]

Typically the temperature of the water inside starts around 6ºC, drops, then ends up a little over 8ºC. It never gets below 0. The water is surrounded by 5ºC gel packs, those have a few -20ºC ice packs around them and the everything is packed inside an EPS case. It never stays constant - I wish it would, it would make everything a lot easier. I'm asking for advice on how to calculate this because right now I do it with real time testing and I need to speed the process up. It doesn't have to be 100% accurate, just a relatively close estimate.

 

[Fancy Moses]

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