The thermal efficiency of dual-column chassis can be improved by re-locating line card to connection plane interfaces to the center of the connection plane, as this allows inter line card channels to be routed in a manner that avoids bisecting the thermal throughways over which convection cooling air is circulated to the line cards. A first seat belt is disclosed having a first end coupled to the lower medial location and a second end coupled to the upper medial location. The disclosed techniques enable alleviating some of the problems that result from distance communication. A switching device is coupled to the fault detection circuit. A heat exchanger inlet opening extends through the duct wall between the inlet manifold and the heat exchanger, and a heat exchanger outlet opening extends through the duct wall between the outlet manifold and the heat exchanger. Furthermore, many of the bottom cycle parts can be obtained from existing reciprocating engines and it is even possible to integrate the top and bottom cycle engines on the same engine block.