Efficiency of optimized bifurcating tree-like and parallel microchannel networks in the cooling of electronics

A bifurcating tree-like network consists of a single inlet channel, which bifurcates over several levels to uniformly distributed microchannels that are vertically connected to a second network for fluid return. Here we introduce a one-dimensional model that considers convective heat transfer from the solid into the liquid as well as entrance and mixing effects. The performance of the bifurcating network is compared with that of a parallel microchannel cold plate branching from a single tapered manifold channel in terms of a constant volume flow rate, pressure gradient, and required pumping power. We optimized both networks independently with regard to global boundary conditions for cooling microprocessors and found a significantly superior performance for the parallel channel cooler. For a constant flow rate, the parallel channel network achieves a more than fivefold higher performance coefficient than the bifurcating tree-like network, while almost four times more heat can be removed for a constant pressure gradient across the networks.