An apparatus includes a circuit having a heat-generating circuit
component, and structure for guiding a two-phase coolant along a path
which brings the coolant into direct physical contact with either the
circuit component or a highly thermally conductive part which is
thermally coupled to the circuit component. The coolant absorbs heat
generated by the circuit component, at least part of the coolant changing
from a first phase to a second phase in response to the heat absorbed
from the circuit component, where the second phase is different from the
first phase.