We review why battery-powered, rechargeable, electric resistive heating is the approach of choice, and propose a device concept that is thin, conforms to the body, weighs under 14 lbs., and is about 2.5 cubic feet in volume. Phase I involves literature research, mathematical modeling, experimental studies, and technical development structured to tightly control design risk. We give utmost attention to the physics of energy transfer from a heating device, through the device-skin interface and skin, tissues below, the body core, and other avenues of energy exchange that circumvent the warming device. During Phase I, we optimize a device specification and analyze its feasibility during the Base Interval, and further verify and enhance these elements in the Option Interval. Our proposal includes a number of specific approaches to key problems that carry significant TGI proprietary content. Generic topics include minimizing system power requirements, applying heat in a fashion that efficiently reaches the body core, and ways to best manage certain significant parameters of patient care
