A heat exchange structure includes elongated air ducts. Each air duct has a first opening and a second opening at two ends of the air duct to allow air to enter and exit the air duct, respectively. The heat exchange structure includes an exterior heat exchange surface and interior heat exchange surfaces, in which the exterior heat exchange surface is configured to receive thermal energy from heat generators that are mounted on the exterior heat exchange surface, and the exterior heat exchange surface dissipates a portion of the thermal energy received from the heat generators and transfers another portion of the thermal energy to the interior heat exchange surfaces. The interior heat exchange surfaces are in the elongated air ducts and configured to exchange thermal energy with air flowing in the air ducts, enhancing air flow in the air ducts by buoyancy of heated air.