Clothing that protects first responders from chemical, biological, and nuclear threats can subject the individuals to heat stress. These hazardous environments require the use of PPE with level A protection, which can significantly diminish the ability of the body to reject heat to the external environment, leading to symptoms ranging from muscular weakness, dizziness and physical discomfort to more severe, life-threatening conditions such as heat exhaustion or heat stroke. RTI proposes to develop a miniature refrigeration unit, which utilizes a vapor compression cycle, to transfer heat from the encapsulated individual to the outside environment. This project will provide a portable cooling unit with a combination of performance, reliability, size and weight that is currently not available or possible from conventional designs. Specifically, the proposed cooling system will produce 425BTU/hr (125W) of cooling to a water vest with an average water temperature of 25°C, weigh 1.6kg (without battery), have a volume of 1.0L and require 50W of electrical power. The Phase I effort will concentrate on the thermodynamic cycle, system configuration, material selection, material testing and enhancement through thin film solid lubrication applications, and fabrication of a prototype compressor. Design of the remaining system, components and system testing and integration would be undertaken in Phase II
