An apparatus for cooling an electric machine includes a plurality of fluid channels disposed in a first surface that surrounds at least part of the electric machine. Each of the plurality of fluid channels defines a circumferential path in the first surface, including a first channel section extending at least substantially parallel to first and second circumferences defined by ends of the electric machine, and including a second channel section configured to direct a cooling fluid between a central region of the first surface and an end region of the first surface. The apparatus also includes an outer shell configured to surround the first surface and define a fluid tight chamber between the first surface and the outer shell, the outer shell having at least one inlet through which the cooling fluid is introduced into the chamber and at least one outlet from which the cooling fluid exits the volume.