Interesting. A few questions that come to mind:<p>1. What is the dew point of the compressed air? Many applications using compressed air require very dry air so as to avoid corrosion issues (e.g., air tools) as well as problems related to heating of water vapor (e.g., tires). For small applications, the dew point is reduced using simple traps, silica gel beads, or molecular sieves, but for even-drier air or larger applications, refrigeration-based dehumidifiers are needed. If the use of water in the compression stage leaves the dew point significantly higher than what you get from reciprocating or Roots-type compressors, that added complexity could be a deterrent to adoption.<p>2. What's the energy efficiency of the process? Does the claimed "20% lower cost of ownership" account for the difference in efficiency (whatever it is)?<p>3. What sort of pressures can be achieved with a tabletop or shop-sized compressor? Presumably, this is related to the speed at which the drum is spun, but what are the practical limits?<p>I mean, I use a decent amount of very dry air at 300 bar (yeah...), and I'd love to replace the noisy beast of multi-stage compressor with something quieter and more efficient.