Packout thermal simulator · Relocalize

ColdCast

Build the packout on the first tab. Every physical constant the model uses is on the second tab, with its default and a reset. Results update as you type.

Package

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Outer dimensions (L × W × H)
°C
Wall build-up, outside → inside

Any construction works as a stack of layers: paper, foil, film, foam, liners, air gaps. An air gap takes its radiation from the two faces beside it, so a foil face next to a gap is what makes a reflective liner work. Foil, film and gaps hold almost no heat and are treated as pure resistance.

Coolant

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Pack size (L × W × thickness)
°C

Payload

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Item size (L × W × height)
°C

Layout

▶

Layers from the floor up. Items in a layer sit side by side; the count sets how much of the floor they cover.

Stack height vs. cavity

Ambient profile

▶

Pass criteria

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°C
°C
h
%

Save & share

The JSON includes the packout, every physics setting and any custom materials. To load a setup, paste its JSON below.

Section view

side section, to scale

3D view

drag to turn, scroll to zoom
front walls and lid cut away

Temperature

    Coolant melted

    share of latent capacity used

      Compare runs

      pinned runs vs. the current setup

        Data table

        hourly values of the current run

        ColdCast model: 1-D multilayer conduction through six faces (area taken at each layer's depth); outside films = convection + radiation at each face's emissivity; inside, every surface exchanges convection and radiation with one well-mixed air/radiant node (exact for two-surface radiation); a floor-to-lid stack of slabs with melting and freezing (enthalpy method); contact resistance between touching surfaces; optional surface underneath, side-wall contact, seam leak and air exchange. Uncalibrated results rank configurations well; calibrate the Physics settings to a logger run for absolute hold times.