Thermo-economic analysis of the impact of the interaction between two neighboring dry cooling towers on power generation of dual thermal power units and the energy-efficient operation strategy

Abstract

Thermo-hydraulic behavior of the dry cooling tower and thermodynamic performance of the power unit was coupled by a well-developed computational framework. The interaction between two neighboring towers was detected through a numerical model under variable working conditions, and the impact of cooling performance variation of each tower on cycle efficiency of the corresponding unit was quantified by a thermo-economic model. Results showed that tower interaction mostly impacts heat rejections of radiators at the neighboring halves of both towers. A higher unit load ensures both towers better cooling performances subject to crosswind. The unfavorable wind-effect on cooling behavior of the upstream tower mitigates with increasing wind attack angle, while that on the downstream tower varies little initially and drops sharply as wind attack angle approaching 90°. For each unit, thermodynamic cycle efficiency is more sensitive to crosswind under a higher unit load. Cycle efficiency grows with unit load at low wind speeds, but generally increases and then decreases with unit load at medium–high wind speeds. Dual units should operate at the same load to maximize operational energy efficiency. Otherwise, the unit corresponding to the upstream tower should follow higher and lower load commands under small-medium and large wind attack angles, respectively.