Effect of Inlet Air Turbulence on the Cooling Performance of Solar Enhanced Dry Cooling Towers

Solar enhanced natural draft dry cooling towers (SENDDCTs) use solar energy to reheat the air coming from vertically arranged heat exchangers for tower performance enhancement. The SENDDCT produces large differences in air density between the inside and outside of the tower (i.e., the tower driving force is intensified), and therefore enhances the ventilation inside the tower for better cooling. How to efficiently introduce solar energy for reheating the air is important for a SENDDCT. This paper is to study different air turbulence regimes so as to enhance the heat transfer in the solar reheating section. The different air turbulences are achieved by changing the endothermic ground from flat to rectangular ribs. A 3-D model is developed using FLUENT 18.0 to simulate the operation of the above-mentioned SENDDCTs. The model will be validated by comparing with literature. According to the simulation, the rectangular-rib SENDDCT enhancement can go up to 13.1% by increasing the heat rejection rate of the flat SENDDCT from 133 to 149 MW, which proves that the cooling performance of the SENDDCT can be improved by intensifying the inlet air turbulence.