Enhanced Dropwise Condensation for Improved Dry Cooling Efficiency

With the increase of energy consumption and water stress, power plant cooling, which accounts for 40% of fresh water withdrawal, has been received more and more attention. Dry cooling technology is currently the most feasible solution to reduce this water consumption. However, the cost of the dry cooling system can be more than 5 times of the typical wet cooling system. Increase the dry cooling efficiency and reduce the cost will help the adaption of this type of technology and therefore reduce the cooling water consumption of power plants. The proposed coating technology, Self-Assembled Monolayer (SAM), is able to promote the dropwise condensation, a more efficient condensation mode, to increase the dry cooling efficiency and consequent reduce the capital and operational cost of the dry cooling system. Compared to many other existing hydrophobic coating technologies, the SAM coating has thickness 1 ~ 3 nm that is able to minimizes additional thermal resistance contributed from coating itself, which results much higher heat transfer improvement. Phase I has successfully demonstrated the improvement of condensation heat transfer (six-fold compared to typical filmewise condensation) with the proposed coating technology in the bench top test loop. Phase II plans to further demonstrate the proposed coating technology in the actual components as well as subscale system. Commercial Applications and Other Benefits: In addition to the dry cooling system, the proposed surface treatment can also be used for other industrial cooling and condensation applications.