A power delivery system includes a group of removable power cells. Each power cell includes a water cooled heat sink, an air intake, and an air output. The system also includes a heat exchanger. The heat exchanger draws air from the cells, cools it, and recirculates the cooled air to the cells via each cell's air intake. The cell may be designed so that components that are not near the heat sink are cooled by air from the intake before that air reaches the heat sink.