Systems and methods based on the systems to convert a portion of thermal energy into to mechanical and/or electrical energy including a power generation subsystem (PGSS) comprising a vaporization and power generation subsystem (VPSS) including a heat recovery vapor generator (HRVG) and a turbine T1, a heating and cooling subsystem (HCSS) including three parallel configured heat exchange units HE3, HE4, and HE5, a single heat exchange unit HE2, and a first separator SP1, and a condensing subsystem (CSS) including a final condenser HE1b from a heat source subsystem (HSSS) including a heat source producing an initial heat source stream.