A heat exchange structure includes a plurality of elongated air ducts. The heat exchange structure has an exterior heat exchange surface and interior heat exchange surfaces, the interior surfaces being in the elongated air ducts. The heat exchange structure includes a plurality of heat generators that are distributed on the exterior heat exchange surface along an elongated direction of the air ducts, in which air flowing in the air duct is heated successively by heat from the heat generators, and air flow in the air duct is enhanced by buoyancy of heated air.