A crew cooling system for the M9 Armored Combat Earthmover (ACE)

This paper describes the development and testing of a vapor-compression cooling system for the M9 Armored Combat Earthmover (ACE). The M9 ACE is an 18-ton, fully tracked vehicle designed for combat engineer tasks to ready and maintain the forward battle area for offensive or defensive operations. The M9 ACE has a single crew member in a very small compartment that is exposed to ambient conditions. Due to the proximity of this compartment to the air exhaust from the engine's cooling system, ambient temperatures in the crew compartment can cause heat stress and other physiological problems for the crew. An HFC-134a vapor-compression cooling system was designed to chill water that is circulated through a cooling garment worn by the crew. The cooling system is powered by the vehicle's 24-volt electrical power, is capable of rejecting heat to 150/spl deg/F ambient air, and can withstand the vibration, shock, and other conditions of the battlefield. Two generations of this cooling system were designed, fabricated, lab-tested, and field-tested on the M9 ACE. This paper describes the system and its components in detail, and presents the system performance results from the lab tests and field tests.