robotixonic
Both machines use heat instead of a mechanical compressor, both can operate with essentially no moving mechanical parts, and both exploit partial pressure so a refrigerant can evaporate at a low temperature. The crucial difference is which fluid does which job.
The conventional diffusion-absorption refrigerator, developed by Platen and Munters in the 1920s, uses ammonia as the refrigerant. Hydrogen occupies the evaporator and lowers ammonia’s partial pressure, allowing liquid ammonia to evaporate at a low temperature. The ammonia vapor is subsequently absorbed into water. This is the basic technology that became familiar in gas-powered and RV refrigerators.
From the specific standpoint of a field-built jungle refrigerator, the Einstein–Szilard working-fluid combination arguably makes the better plot device. The Platen–Munters choice has the advantage of commercial precedent, but the hydrogen charge is decidedly the awkward ingredient. Even though once the system is charged the constituent chemicals stay put, I would rather schlep through the jungle with butane in a canister than the requisite amount of hydrogen.
“The Mosquito Coast” is an interesting movie.