A power recovery system using the Rankine power cycle incorporating a two-phase liquid-vapor expander with an electric generator which further consists of a heat sink, a heat source, a working fluid to transport heat and pressure energy, a feed pump and a two-phase liquid-vapor expander for the working fluid mounted together with an electric generator on one rotating shaft, a first heat exchanger to transport heat from the working fluid to the heat sink, a second heat exchanger to transport heat from the heat source to the working fluid.