The comparisons between both heat exchangers designs are shown in Fig. 9(a) and (b) for Nusselt number and friction factor, respectively. For low Reynolds numbers, the manifold-microchannel heat exchanger’s Nusselt numbers are comparable to the highest of all three chevron designs, while its corresponding friction factor is equivalent to the lowest of all three. For high Reynolds numbers, the manifold-microchannel heat exchanger’s friction factor is equivalent to the chevron design with chevron angle of 45, while its corresponding Nusselt numbers are higher than all chevron designs. Unlike chevron heat exchangers, the optimum manifoldmicrochannel results depend not only on Reynolds number but also on geometrical parameters