Heat management devices and structures are disclosed that can be used in lamps having solid state light sources such as one or more LEDs. Some lamp embodiments comprise one or more phase change radiators that utilize the latent heat of fluids to circulate and draw heat away from the LEDs and radiate the heat into the ambient, allowing for the LEDs to operate at a lower temperature. Some phase change radiators according to the present invention can comprise a main radiator body and multiple radiator coolant loops mounted to the body. The present invention relies on the circulation of heated fluid through the radiator body to radiate heat from the LEDs. The heated liquid moves away from the LEDs and is circulated back to thermal contact with the LEDs thought the coolant loops.