Meet the Swedish firm trying to shake up heat pumps

Heat pumps, a type of reverse-refrigerator used for warming homes, are not the type of tech that gets most investors hot and bothered. They were, after all, invented in 1856. Harald Mix and Carl-Erik Lagercrantz, two Swedish financiers, see things differently.

The pair, whose investment group Vargas is behind Northvolt, a battery maker, and H2 Green Steel, which uses green hydrogen to produce steel, sense there are big bucks in replacing…