A condenser is a device which condenses the steam at the exhaust of turbine. It serves two important functions.Firstly, it creates a very low ( By liquidation steam at the exhaust of turbine, a region of emptiness is created. This results in a very low pressure at the exhaust of turbine.) pressure at the exhaust of turbine, thus permitting expansion of the steam in the prime mover to very low pressure. This helps converting heat energy of steam into mechanical energy in the prime mover. Secondly, the condensed steam can be used as feed water to the boiler. There are two types of condensers, namely:
(i) Jet condenser (ii) Surface condenser

In a jet condenser, cooling water and exhausted steam are together. Therefore , the temperature of cooling water and condensate is the same when leaving the condenser. Advantages of this type of condenser are:low initial cost, less flow area required, less cooling water required and low maintenance charges. However,its disadvantage are: condensate is wasted and high power is required for pumping water.In a surface condenser, there is no direct contact between cooling water and exhausted steam. It consists of a bank of horizontal tubes enclosed in a cast iron shell. The cooling water flows through the tubes and exhausted steam over the surface of the tubes. The steam gives up its heat to water and is itself condensed.Advantage of this type of condenser are : condensate can be used as feed water, less pumping power required and creation of better vacuum at the turbine exhaust. However, disadvantage of this type of condenser are : high initial coast, requires large floor area and high maintenance charges.A surface condensor is shown below