Heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems and heat exchangers are provided which include dissimilar internal configurations. The heat exchangers include multiple sets of multichannel tubes in fluid communication with each other. One set of multichannel tubes contains flow channels of one shape and size while the another set of multichannel tubes contains flow channels of a different shape and/or size. The dissimilar flow channels within the multichannel tube sets allow each set of tubes to be configured to the properties of the refrigerant flowing within the tubes.