A rack and system for cooling computing devices such as in a data center is disclosed. In one embodiment, the rack supports computing devices and comprises planar annular sector or trapezoidal shelves, each having one or more positions for holding computing devices. The rack may be configured to be connected to other similar racks to form a vertical geometric prism or annular cylinder, which may be tapered, and the computing devices may be installed to discharge exhaust at an angle. A number of vertical supports may hold the shelves in a vertically spaced arrangement to from a helix within the prism or cylinder. An air barrier may be affixed to the rack and have openings permitting exhaust air to flow from the computing devices through the air barrier. The helix formed by the shelves may channel the airflow generated by the computing devices into a vortex to improve cooling.