This Small Business Innovation Research Phase I project aims to further develop a breakthrough compression technology for industrial compressed air applications. We have developed an innovative hybrid-rotor geometry which leads to extremely high power density and enables the use of a proprietary liquid injection system that can directly cool the gas as it is compressed, leading to near isothermal compression. This combination can result in an increase of over 30% in efficiency and an order of magnitude higher compression ratio than is achievable with conventional compression technology. The key objectives of this effort are to verify the technology's applicability in industrial compressed air applications and build and test a full-scale prototype to validate performance models. The successful completion of this project will lead to the commercialization of a product that will provide a step-change in the performance of industrial compressed air systems. The broader impact/commercial potential of this project is widespread. Industrial users are responsible for approximately one-third of all power consumption in the US, or around one trillion kilowatt-hours per year. Ten percent of all industrial power use, or roughly 100 billion kilowatt-hours per year, is consumed in the production of compressed air, with that percentage going as high as 20% in certain process-intensive industries. The technology being investigated in this proposal has the potential to improve the efficiency of air compressors by over 30%. Combining these savings with other system-level improvements could reduce the power required to run compressed air systems by a factor of two. Along with the dramatic potential for energy savings, there is also an enormous market for compressors, with 2007 worldwide shipments of air and gas compressors approaching $10 billion. New compressors used in industrial air applications were worth $600 million in the US alone in 2009. A higher efficiency compressor has the potential to capture a large share of this market. Finally, this technology could also be applied for other compression and turbomachinery applications, with far-reaching impact and enormous commercial potential