A lighting assembly includes a cooling system configured to enable the dissipation of a large amount of energy in the form of heat generated by a light source. Heat is dissipated without heating surrounding components, such as the one or more power supply units and device electronics. The cooling system is configured as a gravity feed system that does not require a powered fluid pump. In some embodiments, the cooling loop is configured as a thermal siphon that uses a boiling fluid to transport heat between the evaporator and the radiators. In some embodiments, the evaporator also functions as a device chassis, which reduces the overall part count. In some embodiments, the light source is a plurality of LEDs.