The present invention is a system and method of power medium expansion that functions with a rate of efficiency higher than systems found in prior art. Novel features of the system increase the overall efficiency with the use of a power medium that begins the cycle in the liquid state and enters the gaseous state. An additional novel feature is the use of additional heat that may also increase the overall cycle efficiency. Another additional novel feature is recuperating energy that can supplement the phase change of the power medium along with isolating the components from the ambient.