Patent ID: 7931071

Claim:
A heat exchanger comprising: an evaporation side heat pipe in which a working fluid flowing therein is heat exchanged with an exterior high-temperature fluid passing therethrough to be evaporated; a condensation side heat pipe in which the working fluid flowing therein is heat exchanged with an exterior low-temperature fluid passing therethrough to be condensed; and an evaporation side inner fin located in the evaporation side heat pipe to increase a heat transmission area of the evaporation side heat pipe with the working fluid, wherein: the evaporation side heat pipe and the condensation side heat pipe are connected to form a closed cycle in which the working fluid circulates between the evaporation side heat pipe and the condensation side heat pipe; the evaporation side heat pipe is arranged such that the working fluid flows in the evaporation side heat pipe in a direction different from a horizontal direction; and the evaporation side inner fin located in the evaporation side heat pipe has a bottom end that is positioned above a top surface of the working fluid in a liquid state.