Cooling towers are structures for cooling water or other working medium to near-ambient temperature. The primary use of large, industrial cooling towers is to lower the temperature of the cooling water used in power plants, petroleum refineries, petrochemical plants, natural gas processing plants and other industrial facilities. It is desirable to cool the water rather than simply discharging it because the cooling water is typically demineralized and it is cheaper to cool it rather than getting more demineralized water. Furthermore, discharging large amounts of hot water may raise the temperature of the receiving river or lake to an unacceptable level for the local ecosystem. A cooling tower serves to dissipate the heat into the atmosphere instead and wind and air diffusion spreads the heat over a much larger area than hot water can distribute heat in a body of water.