Chen Li, PhD - US grants

1357920
Li

Hybrid cooling, as proposed here, will have direct impact on power plants, particularly in increasing the power generation efficiency, reducing approximately 70% water usage (compared to cooling towers) and by alleviating the dependence of air cooling performance on the ambient conditions (i.e. weather conditions; ambient air temperature and moisture, cross winds etc.). The foundational knowledge gained from this project will stimulate the transition from current cooling equipment of power plants to this unique and novel technology. The substantial water saving will help relieve the water crisis facing US and the world. By active dissemination of the fundamental findings, it will offer the scientific community a unique understanding of effectively cooling large scale power plant units in an efficient environment-friendly, and sustainable way.

In this research, novel heat-pipe condensers cooled by on-demand sweat-boosted air cooling will be developed to achieve unprecedented cooling capability and substantially reduce the size and footprint of air-cooled condensers (ACC), with a minimal penalty in power production. This can be achieved by innovatively engineering phase change heat transfer to drastically enhance three major heat transfer processes in ACC. Specifically, heat acquisition will be enhanced by dropwise condensation on robust Nickel alloy coatings created by atmospheric plasma spray (APS); temperature difference can be significantly reduced by highly conductive heat pipes (as the condenser core) enabled by novel hybrid microscale wick structures; and the heat rejection process will be dramatically enhanced by devising sweat-evaporation that mimics the primary mechanism of mammals to effectively dissipate heat during physical exercise. Novel nanowicks will be developed from functionalized carbon nanotubes (CNTs) to realize evaporation and create durable self-cleaning coatings. The heat and mass transfer on micro/nano-engineered surfaces will be experimentally and numerically studied. Component level models will be integrated in a Virtual Test Bed (VTB) to achieve high fidelity modeling of ACCs and power plants. Compared with conventional ACCs, the capital cost can be potentially reduced by 67% as estimated in our preliminary model. To achieve the objectives of this three-year project, five major research tasks will be carried out: 1) designing and evaluating condensers in a VTB; 2) devising sweat-boosted air cooling; 3) developing high performance heat pipes as the core of the condenser; 4) enabling dropwise condensation for heat acquisition; and 5) benchmarking modeling in a lab scale condenser.

Underrepresented student support is emphasized in this project. Outreach activities geared towards high school students, teachers, and general public will be carried out.