An LED lighting system powered by an AC power source comprising a rectifier module configured to provide a rectified output to a first group of LED devices and a second group of LED devices electrically coupled to the first group of LED devices. The dual-chamber container includes an inlet fluid port and outflow fluid port which may be coupled directly to corresponding fluid port connectors on a temperature control unit, or an intervening fluid coupling assembly may convey heat transfer liquid between the control unit and the dual-chamber container. Two screw holes are defined in opposite side faces of the heat sink.