A lighting assembly for cooling a light source, the lighting assembly comprising: a. a light source having a vertically aligned thermal exchange surface that extends in a vertical direction; b. an evaporator having a side thermal exchange surface thermally coupled to the vertically aligned thermal exchange surface of the light source, wherein the evaporator comprises a reservoir and a fluid within the reservoir, the evaporator is configured such that at least a portion of the fluid is vaporized by heat transferred from the light source; and c. a cooling loop coupled to the evaporator, wherein the cooling loop comprises a transfer pipe coupled to the evaporator, a radiator coupled to the transfer pipe, and a return pipe coupled to the radiator and to the evaporator, wherein the return pipe includes a first end coupled to the radiator and a second end coupled to the evaporator, the return pipe is configured and aligned having the first end of the return pipe positioned higher than the second end of the return pipe and an entirety of the return pipe is positioned higher than a bottom surface of the evaporator thereby enabling gravity feeding of fluid from the radiator to the evaporator, further wherein the radiator is configured to receive vapor from the evaporator via the transfer pipe and to condense the vapor to fluid, and the radiator is configured to gravity feed fluid to the return pipe, wherein the radiator comprises an input header coupled to the transfer pipe, the input header configured to laterally distribute the vapor received from the transfer pipe, wherein a fluid level of the fluid in the reservoir is at least as high as a highest vertical point of the light source. a. a light source having a vertically aligned thermal exchange surface that extends in a vertical direction; b. an evaporator having a side thermal exchange surface thermally coupled to the vertically aligned thermal exchange surface of the light source, wherein the evaporator comprises a reservoir and a fluid within the reservoir, the evaporator is configured such that at least a portion of the fluid is vaporized by heat transferred from the light source; and c. a cooling loop coupled to the evaporator, wherein the cooling loop comprises a transfer pipe coupled to the evaporator, a radiator coupled to the transfer pipe, and a return pipe coupled to the radiator and to the evaporator, wherein the return pipe includes a first end coupled to the radiator and a second end coupled to the evaporator, the return pipe is configured and aligned having the first end of the return pipe positioned higher than the second end of the return pipe and an entirety of the return pipe is positioned higher than a bottom surface of the evaporator thereby enabling gravity feeding of fluid from the radiator to the evaporator, further wherein the radiator is configured to receive vapor from the evaporator via the transfer pipe and to condense the vapor to fluid, and the radiator is configured to gravity feed fluid to the return pipe, wherein the radiator comprises an input header coupled to the transfer pipe, the input header configured to laterally distribute the vapor received from the transfer pipe, wherein a fluid level of the fluid in the reservoir is at least as high as a highest vertical point of the light source.