An eccentric shaft assembly comprising: a first eccentric shaft having an axis of rotation and a center of mass that is radially offset from the axis of rotation, the first eccentric shaft comprising: an interior surface forming a recess therein; an exterior surface; at least one first fluid inlet extending between the interior surface and the exterior surface; and at least one first fluid outlet extending between the interior surface and the exterior surface, wherein the interior surface of the first eccentric shaft comprises a first bearing surface between the at least one first fluid inlet and the at least one first fluid outlet; a first bearing subassembly engaging the first bearing surface; a second eccentric shaft disposed in the recess of the first eccentric shaft, the second eccentric shaft having the axis of rotation and a center of mass that is radially offset from the axis of rotation, the second eccentric shaft comprising: a second bearing surface engaging the first bearing subassembly opposite the first bearing surface; and at least one first fan blade for rotating about the axis of rotation to force a fluid to enter the recess through the at least one first fluid inlet and exit the recess through the at least one first fluid outlet. an interior surface forming a recess therein; an exterior surface; at least one first fluid inlet extending between the interior surface and the exterior surface; and at least one first fluid outlet extending between the interior surface and the exterior surface, wherein the interior surface of the first eccentric shaft comprises a first bearing surface between the at least one first fluid inlet and the at least one first fluid outlet; a first bearing subassembly engaging the first bearing surface; a second eccentric shaft disposed in the recess of the first eccentric shaft, the second eccentric shaft having the axis of rotation and a center of mass that is radially offset from the axis of rotation, the second eccentric shaft comprising: a second bearing surface engaging the first bearing subassembly opposite the first bearing surface; and at least one first fan blade for rotating about the axis of rotation to force a fluid to enter the recess through the at least one first fluid inlet and exit the recess through the at least one first fluid outlet. a first bearing surface between the at least one first fluid inlet and the at least one first fluid outlet; a first bearing subassembly engaging the first bearing surface; a second eccentric shaft disposed in the recess of the first eccentric shaft, the second eccentric shaft having the axis of rotation and a center of mass that is radially offset from the axis of rotation, the second eccentric shaft comprising: a second bearing surface engaging the first bearing subassembly opposite the first bearing surface; and at least one first fan blade for rotating about the axis of rotation to force a fluid to enter the recess through the at least one first fluid inlet and exit the recess through the at least one first fluid outlet. a second bearing surface engaging the first bearing subassembly opposite the first bearing surface; and at least one first fan blade for rotating about the axis of rotation to force a fluid to enter the recess through the at least one first fluid inlet and exit the recess through the at least one first fluid outlet.