BDob Chaparro wrote:
The amount of salt required to achieve 32 degrees usually was 30 percent by weight compared to the ice. I'm sure this kind of extreme performance in the ice bunker cars required frequent reicing.
Probably this is a typo by Bob. An equilibrium mixture of water and ice, no salt, is at 32 degrees (Fahrenheit). Salt additions lower that temperature. The minimum achievable (in the laboratory) with 23 percent salt is -6 degrees (the temperature of the water-salt eutectic, for the technically minded -- you can read about eutectics on Wikipedia). Use of more salt, for example 30 percent, is just insurance. I have read that it was difficult to get an ice reefer below 10 degrees in real life. And BTW, ice cars used for frozen loads were heavily insulated compared to ordinary ice reefers.
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