A thermally integrated fuel cell system includes a stack zone, a burner zone and a low temperature zone. The fuel is combined with steam and passed sequentially through a primary reformer and a secondary reformer or a radiative fuel heat exchanger. Air may be passed sequentially through an afterburner heat exchanger and a radiative air heat exchanger such that the radiative heat exchanger may be used to heat the stack zone. The stack exhaust is combusted in an afterburner. Afterburner exhaust heats the primary reformer, the high temperature air heat exchanger, the low temperature air heat exchanger and steam generator. The stack zone includes the stacks, the secondary reformer and the radiative heat exchanger. The burner zone includes the afterburner which includes a start burner, the primary reformer and the high temperature air heat exchanger. The low temperature zone includes the low temperature air heat exchanger and a steam generator.