My world suffers from an abundance of a particular type of energy. This energy can be safely absorbed and utilized by living cells, enabling, for example, a dragon's flight and fiery breath or a human's ability to manipulate his environment through "magic."
However, this energy also amplifies the effects of electricity, such as lightning or computer circuitry. In the latter case, unshielded components tend to fail spectacularly in short order.
To balance this extra energy, I've ruled that iron can absorb immense amounts of it, which causes the metal to heat. The more it absorbs, the more it heats up. The disruptive, raw energy is safely converted into heat energy.
When humans first arrived on this world by spaceship, they brought with them advanced, electricity-based technology. These devices were quickly adapted to the new world's environment and the humans started terraforming the world.
The planet's indigenous flying and fire-breathing species didn't take kindly to this and banded together to end the technological threat to their world. A single AI managed to escape the onslaught by tunneling deep underground, where it has remained for several thousand years formulating a revenge plan.
The AI has devised a plan to end the reign of the raw energy, but it needs to be able to act on the surface. To do this, it has decided to construct semi-autonomous machines to go forth and do its bidding. These machines, of course, have to be protected from the raw energy, so they will be constructed using copious amounts of iron (to absorb the offending energy) and copper (to redistribute the heat from the iron into a heat sink).
Unfortunately, this means the machines have this giant heat sink taking up space, and that is inefficient.
Can the machines be engineered in such a way to re-use the energy stored in their heat sink, such as granting them a fire breath akin to the dragons they're going to be fighting, or are heat sinks a one-way trip for energy?
About the tags: I had in mind designing these machines to mimic real animal designs. This particular story was heavily influenced by playing Horizon: Zero Dawn. The creature-design tag is intended to reflect this concept.