In evaporative condenser, steam circulates in pipes surrounded by water spray, as shown in Fig. 8.9. It is used when there is scarcity of cooling water. The cooling water is allowed to evaporate under a small partial pressure. It consists of gilled piping bent to form many rows and is placed vertically. Steam passes through these pipes. Pumped water is sprayed from the top and descends down forming a thin film over the pipes. A natural or forced air draught causes the evaporation of the water film. Steam while circulating inside the pipes, latent heat of evaporation is removed from steam and thereby the steam gets condensed. This mode of heat transfer reduces the cooling water requirement of condenser to 10% of the requirement for surface condensers. The water particles carried with air due to high velocity of air are removed with the help of eliminator. This type of condenser works better in dry weather.
Figure 8.9 Evaporative condenser
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