Evaporative towers are quite noisy machines, engendering noise emissions in the lower frequency range that can be heard even at long distances. Hence, especially in case of installation of a tower nearby a residential area, noise pollution is a factor that has absolutely not to be ignored.
In this case it is mandatory to choose centrifugal towers equipped with silencers mounted both in suction and exit line. This is anyway a solution that boost power consumption costs. Otherwise, it’s possible to implement axial fans with special low-noise blades, or even better it will be suitable to study the installation site of the tower, in order to possibly consider the presence of reflecting walls or surfaces, or obstacles in function of natural noise-barriers limiting noise-diffusion.
In fact there are several noise-reduction systems, based on the kind of evaporative tower (being it an open circuit tower, a closed-circuit evaporative cooler or an evaporative condenser), that can be adopted:
Usually, axial fans are the most cheaper solution in terms of energy consumption compared to centrifugal fans, which are very much more consuming, but they are difficult to be silenced. The best choice, in case noise becomes a problem, will therefore be low-noise type axial fans.
In addition to ventilation, another source of noise at higher frequency in evaporative towers is the splash of the water falling inside the basin. This is another element that can impact the selection of the most suitable kind of cooling tower. A forced draft tower typically has a closed basin inside the carpentry, which clearly reduces the splashing noise of the water. In case instead of an induced type tower, with fans on top and basin in view, then there will be a continuous noise of splashing water falling on the water surface into the collection basin. Splashing noise reduction systems are employed in this case, which are installed on the surface of the water muffling the waterfall noise.