Heat engines made of quantum dot (QD) superlattice nanowires (SLNWs) offer promising applications in energy harvesting due to the reduction in phonon thermal conductivity. In solid state electrical generators (refrigerators), one needs to generate (remove) a large amount of charge current (heat current). Consequently, a high QD SLNW density is required for realistic applications. This study theoretically investigated the properties of power factor and electron heat rectification for an SLNW array under the transition from a one-dimensional system to a two-dimensional system. The SLNW arrays show the functionality of heat diodes, which is mainly attributed to a transmission coefficient with a temperature-bias direction dependent characteristic.