3. Non-mixing type condensers
The exhaust steam and the coolant water will not
be in direct contact with each other.
Steam passes over the tubes, which contain the coolant water.
There can be single pass and two pass condenser in this form.
In single pass, the Water will flow in only one direction.
In multi pass the water will flow in one direction in a set of
tubes and flow in other direction in other set of tubes.
4. Reasons for inefficiency in Surface Condensers
Due to low air pressure in the condenser, air may leak into the
condenser.
Pressure drop in steam flow across tubes.
Conduction through the tubes is not perfect.
More than half of the heat supplied by fuel is rejected to the
condenser cooling water.
Air is extracted with a large content of water vapor.
5. Comparison of Jet and Surface Condensers
Jet Condenser Surface Condenser
Cooling Water and Steam Mix Cooling Water and Steam are not mixed
Low Manufacturing cost High
Lower Maintenance Higher Maintenance
Requires Small floor space Requires Large floor space
Condensate cannot be used as feed water
Unless coolant is free from impurities.
Condensate can be used as feed water.
More power is required for air pump Less
Less cooling water is required More
Simple plant Complex
Less suitable for High capacity plants due
to lower vacuum efficiency.
Suitable for high capacity plants due to high
vacuum efficiency.
