Evaporative cooling is one of the most efficient cooling systems compared to other cooling methods. To understand this, we are going to know a basic concept in relation to cooling towers: the wet bulb.
What is wet bulb temperature?
An important physical concept allows us to better understand how cooling towers work: it is the wet bulb temperature, fundamental in the theory of operation of all evaporative systems and, in particular, in cooling towers.
In practice, this parameter defines exactly what the “worst” temperature and relative humidity conditions are in the installation area. It provides an accurate reference to the theoretical output temperature achievable by the cooling tower.
Cooling towers – Efficiency
Evaporative towers are still the most used cooling device both in civil sector and, industrial sectors. Given its simplicity of construction, combined with the high efficiency in terms of cost/kW dissipation ratio. Moreover, there are no particular moving parts. Only one fan (which can be installed both in suction and discharge). On the other hand, the electricity consumption is really reduced, if compared to other systems in use for the same purposes.
Efficiency in cooling towers is especially demonstrated even in the presence of high amounts of heat to be dissipated. For example, in steel, chemical or power plants for electricity production, cooling towers are unrivalled in terms of electrical energy used and space required for installation.
We should not forget that temperatures that can be reached in terms of chilled water are far below the ambient temperature. This is due to the fact that evaporation systems operate by exploiting the latent exchange of evaporation (the minimum limit reached by water is the wet bulb temperature).