Abstract: A semi-passive cooling system for an armored vehicle includes an intermittent pressure source, an accumulator for storing pressurized fluid from the intermittent source, and a mechanism to control the pressure in the accumulator. The system also includes a water reservoir and automatic controls for stabilizing pressure in the reservoir at a level lower than the accumulator's pressure. A sheet of water-absorbent, wicking skin on an exterior zone of the vehicle receives pressurized water from the reservoir in response to signals from a heat sensor at the exterior zone. The sensors signals open a valve in a supply line connected between the reservoir and the sheet, the valve remaining open for a predetermined interval.