Packing my cooler for a camping trip made me wonder if there’s anything better than ice to keep my beer cool.
Water is an outlier material in terms of cooling capacity. A liter of water ice, taking into account its phase transition when it melts, would have a cooling capacity of 421 kJ as it goes from -20 °C in my freezer to room temperature at +20 °C.
According to ChatGPT, there are hardly any materials that beat water ice in terms of cooling capacity. The best seems to be lithium chlorate trihydrate (LiClO₃·3H₂O), which comes in at 570 kJ per liter. Note how it’s a hydrate, meaning that it has three water molecules as part of its structure. The water molecules in ice aren’t packed that tightly, resulting in empty space between them. That’s why ice is lighter than liquid water and floats on it. The reason lithium chlorate trihydrate beats ice in terms of cooling capacity is because in its solid crystal form, it packs more water molecules into the same volume.
Nehaveigur 