An additive manufacturing apparatus , the additive manufacturing apparatus comprising: a build unit comprising a powder delivery mechanism, a powder recoating mechanism, and an irradiation beam directing mechanism comprising an electromagnetic radiation emission system component; a build platform ; a thermal control apparatus comprising a body defining a centerline axis extended along a height and a circumferential direction extended relative to the centerline axis , the body forming a flow circuit within the body , and wherein the body forms an inlet opening and an outlet opening each in fluid communication with the flow circuit , wherein the flow circuit is extended in parallel flow arrangement along the circumferential direction from the inlet opening to the outlet opening , and wherein a cavity is extended at least partially through the body along the centerline axis , wherein the body of the thermal control apparatus forms a plurality of lobes at the flow circuit , and wherein a slot is extended along a radial direction from the centerline axis between diametrically-opposed lobes of the plurality of lobes , and wherein the slot is extended at least partially along the height, and wherein the electromagnetic radiation emission system component is positioned through the slot and the cavity formed at the body of the thermal control apparatus ; a fluid flow device configured to provide a flow of heat transfer fluid to the thermal control apparatus through the inlet opening and to receive the flow of heat transfer fluid from the outlet opening of the thermal control apparatus ; and a flow conduit providing fluid communication of the flow of heat transfer fluid between the fluid flow device and the thermal control apparatus . a build unit comprising a powder delivery mechanism, a powder recoating mechanism, and an irradiation beam directing mechanism comprising an electromagnetic radiation emission system component; a build platform ; a thermal control apparatus comprising a body defining a centerline axis extended along a height and a circumferential direction extended relative to the centerline axis , the body forming a flow circuit within the body , and wherein the body forms an inlet opening and an outlet opening each in fluid communication with the flow circuit , wherein the flow circuit is extended in parallel flow arrangement along the circumferential direction from the inlet opening to the outlet opening , and wherein a cavity is extended at least partially through the body along the centerline axis , wherein the body of the thermal control apparatus forms a plurality of lobes at the flow circuit , and wherein a slot is extended along a radial direction from the centerline axis between diametrically-opposed lobes of the plurality of lobes , and wherein the slot is extended at least partially along the height, and wherein the electromagnetic radiation emission system component is positioned through the slot and the cavity formed at the body of the thermal control apparatus ; a fluid flow device configured to provide a flow of heat transfer fluid to the thermal control apparatus through the inlet opening and to receive the flow of heat transfer fluid from the outlet opening of the thermal control apparatus ; and a flow conduit providing fluid communication of the flow of heat transfer fluid between the fluid flow device and the thermal control apparatus . <EOS>