Apparatus for transferring heat from a heat source to air

A network access node for a wireless communication system, wherein the network access node comprises an apparatus for transferring heat from a heat source to ambient air while the apparatus is connected to the heat source, and wherein the apparatus comprises:

• a heat sink comprising a heat sink base and a plurality of primary fins connected to the heat sink base;
• and
• a heat sink front,
• wherein the heat sink base is configured to be thermally coupled to the heat source,
• wherein each primary fin of the plurality of primary fins comprises one or more conduits,
• wherein the heat sink base comprises a first chamber,
• wherein the first chamber and the one or more conduits together form a common space sealed off from the ambient air surrounding the apparatus,
• wherein the first chamber and the one or more conduits together enclose a heat-carrying fluid in the common space formed by the first chamber and the one or more conduits,
• wherein, at the heat sink front, the one or more conduits of a first primary fin of the plurality of primary fins are sealed off from the one or more conduits of a second primary fin of the plurality of primary fins,
• wherein the first primary fin opens into a first condenser chamber and the second primary fin opens into a second condenser chamber, and
• wherein flaps are provided between the first condenser chamber and the second condenser chamber.