Enlarge (credit: Jorg Greuel)

Heat pumps are the most energy-efficient way of controlling indoor temperature. By moving heat between locations, they avoid the inefficiencies of generating heat in the first place. But that doesn't mean they can't be made more efficient.

Most current heat pumps rely on materials that exhibit large changes in temperature in response to changing pressures, but the energy required to pressurize them gets lost when they're cycled back to a low-pressure state, absorbing heat from their surroundings. That has gotten people interested in electrocaloric devices, where changes in temperature are driven by storing charges in a material. Since it essentially acts as a big capacitor, much of the electrical energy involved can be pulled back out as the system cycles.

But capacitors aren't especially mobile, so electrocaloric systems tended to use fluids to move heat into and out of the capacitor as it cycles. Now, however, researchers have developed an electrocaloric system that moves itself between hot and cold environments, radically simplifying the system and eliminating some of the energy required for it to operate. They even demonstrate it effectively cooling a computer chip.