Water evaporation accounts for 70% eighty% of the water consumed in cooling towers.
The precise quantity of water evaporated is determined by the wet-bulb temperature and by the cooling demand of the system.
Upon evaporation, the water leaves behind salts, carbonates and other solids, which might be added to these contained within the water remaining in the circuit, regularly increasing their concentration.
To regulate the focus of salts and carbonates and different dissolved solids, it’s required to purge water from the basin. This water blow-down represents approximately 20-30% of the water consumed within the towers.
The cooling tower also acts as a mighty air cleaner, absorving dirt and bacteria suspended within the air which accumulate at the basin of the cooling tower.
Power Effectivity of Cooling Towers:
The efficiency of a cooling tower degrades when the effectivity of the heat switch process declines. When water evaporates from the cooling tower, the remaining minerals depart scale deposits on the surface of the tower fill. This scale build-up acts as a barrier that prevents the transfer of heat from the water to the air.
Dirt, algae and sediment collect within the water basin together with the remaining minerals from the evaporated water, and journey via the cooling water circuit creating deposits and even clogging the spray nozzles. This causes uneven water distribution over the filling, leading to uneven air flow and a decreased heat switch floor area.
The reduced heat switch capacity reduces the working effectivity of the towers and the energy efficiency of the condensing system (i.e. power consumption of the compressor).
Disadvantages of chemical water treatment:
– Fails to remove all the dirt and keep clean of scale the cooling tower’s fill, affecting the cooling effectivity of the tower.
– Requires to take care of low cycles of concentration, resulting in bigger water consumption resulting from blow-down.
– High cost.
– Limited reuse of blow-down water.
– Harms the setting.