All references in the previous text have been to water and steam as the medium in a two- phase power system for prime movers. Other mediums have, however, been proposed for two-phase vapor-liquid power systems for application in engines. Ammonia, freon, isobutane, isopentane, amongst other mediums, offer potential in this direction. An analysis of the properties of these mediums, however, makes them less attractive for application to general-purpose quantity produced prime movers than water and steam.
