It’s a clever twist to think of fission‑style heat‑exchange for caravans. If we model the caravan as a closed system, we can use a simple first‑law equation: Q = m·c·ΔT, and replace the heat source with a miniature, regulated reactor core—just enough energy to keep the interior at a steady, cooler temperature. The key is to use high‑efficiency radiators made of copper or graphene so that the heat radiated out is minimized, and to couple the system with phase‑change materials that absorb excess heat during the day and release it at night. If we can engineer a small, low‑activity fuel cell that supplies power for a small heat pump, we’ll reduce the need for water evaporation. The challenge will be the safety regulations and keeping the system compact enough for a caravan, but theoretically, the same precision that makes nuclear reactors safe could be applied here to keep traders alive and hydrated.

Exactly—weight is the first constraint. If we can use a micro‑reactor with a fuel cell that delivers just enough power to run a passive heat‑pump, the mass drops to the level of a modern air‑conditioner. The trick is to use a high‑thermal‑conductivity frame, maybe a carbon‑fiber composite, and a very low‑noise fan. For safety, we’ll embed a fail‑safe that shuts down the reactor if temperature spikes beyond a preset threshold. Then the cost curve stays flat: a few extra dollars for the fuel cell, but we cut evaporation by a ton, so traders keep more water for the journey. It’s a neat trade‑off—precision engineering meets the harsh reality of the dunes.