A particular counter-current flow division has been introduced to improve the thermal and hydraulic performances of the flow through two isotherm parallel plates. It has been constructed by inserting two zero thickness and impermeable flat plates within the parallel-plate channel to establish a central and two external sub-channels. The total flow rate has been subdivided to two streams for supplying into the central and two external sub-channels in counter-current directions. The effect of the cross section ratio on the thermal and hydraulic performances has been investigated for two flow division regimes. The obtained results showed that a better thermal performance could be enhanced when the cross section of the central sub-channel was greater than the external ones. Regarding the overall performance, it has been concluded that the best performance could be enhanced when the flow and cross section were equally subdivided. In this particular case, the percent of the heat transfer enhancement compared to the single-pass channel was 50%. Meanwhile, the power consumption increment of the proposed flow arrangement significantly decreased compared to the two previously proposed double-pass arrangements. It seems that the proposed flow arrangement is better alternative for double-pass arrangement.
