Investigation of 3D manifold architecture heat sinks in air-cooled condensers

Abstract

Power plants account for a high rate of freshwater utilization in the United States. Use of air-cooled condensers (ACC) can significantly reduce or completely eliminate freshwater withdrawals for steam-electric plants but suffer from low heat transfer of single-phase air flow. In the current study, we experimentally and computationally investigate the thermal-hydraulic performance of the air-side of a traditional ACC heat sink (EVAPCO fins) and conduct an extensive comparative CFD study of a novel 3D manifolding architecture heat sink design. A parametric investigation was performed on the 3D manifold heat sinks with fin height ranging from 7.3 to 15.3 mm, three fin densities with fin pitch ranging from 1 to 3 mm, and fin angles between 0° and 45°. It is concluded that there is not a single optimal design over the range of flow rates/heat flux, and the heat sink performances are a strong function of the target operating heat flux. Overall, various manifold designs were able to offer improved COP over EVAPCO fins that covered a large range of the operating heat fluxes. Manifold designs also require less fin array material, making them a good alternative for EVAPCO ACC systems if it is desired to increase the heat flux by 3 times for the existing EVAPCO units.