Systems and methods are provided for the recovery mechanical power from heat energy sources using a common working fluid comprising, in some embodiments, an organic refrigerant flowing through multiple heat exchangers and expanders. The distribution of heat energy from the source may be portioned, distributed, and communicated to each of the heat exchangers so as to permit utilization of up to all available heat energy. In some embodiments, the system utilizes up to and including all of the available heat energy from the source. The expanders may be operatively coupled to one or more generators that convert the mechanical energy of the expansion process into electrical energy, or the mechanical energy may be communicated to other devices to perform work.