A numerical study on interactions between three short natural draft dry cooling towers In an in-line arrangement

Abstract Natural draft dry cooling tower (NDDCT) are a favourable choice for the cooling system of concentrating solar thermal power (CST) plants located in arid regions with high solar radiation. However, additional cooling towers may be required as the capacity of the CST plants is increased. The geometrical arrangement of the NDDCTs is an influencing parameter on the thermo-flow performance of the entire system. The aim of this study was to investigate the effect of tower spacing and wind speed on the performance of three short NDDCTs in an in-line layout. The simulated tower is representative of an actual steel-membrane cooling tower in a campus of the University of Queensland. The geometry of the cooling tower in this study is a cylindrical shape with a horizontally arranged air-cooled heat exchanger, and is 20 m high with a diameter of 12.5 m. This study investigated the effect of two major parameters: wind speeds (0–8 m/s), wind and tower spacings (1.8D, 2.6D, and 4.2D) on the thermo-flow performance of the cooling towers. The interaction of the towers from the bottom and top of the towers were identified at different tower spacings and wind speeds. At all tower spacings, the windward tower protects the middle and leeward towers by deflecting the upcoming wind. The interaction of the towers happens both from the bottom and top of the towers. Finally, it was concluded that enlarging the towers increase the thermal performance of the towers during windy conditions and this may lead in better protection of the windward tower for the leeward ones.