Thermal diode
The term "thermal diode" can refer to: a (possibly non-electrical) device which allows heat to flow preferentially in one direction; an electrical (semiconductor) diode in reference to a thermal effect or function; or it may describe both situations, where an electrical diode is used as a heat pump or thermoelectric cooler. == One-way heat-flow == A thermal diode in this sense is a device whose thermal resistance is different for heat flow in one direction than for heat flow in the other direction.