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Condensation is a process in which the vapor phase of a substance is changed into the liquid phase by removing and transferring heat from the vapor to a cooling medium.[1][2] For the process to take place, the vapor must be saturated and the heat of vaporization must be removed from the vapor.[3]
The condensation of vapors, like the boiling of liquids, plays a very significant role in a great many commercial and industrial processes.
Types of condensation
There are several types of condensation:
- Condensation on direct contact with the cooling surface within a heat exchanger and that surface must be at a temperature cooler than of the saturated vapor. This is the most common type of condensation used in industry and there two ways in which it may occur:
- Filmwise condensation in which a liquid film is formed on the cooling surface. This usually occurs when the liquid wets the surface).
- Dropwise condensation in which liquid drops are formed on the cooling surface. This usually occurs when the liquid does not wet the surface. Dropwise condensation is difficult to sustain reliably and, therefore, industrial heat exchangers are typically designed to operate in filmwise condensation mode.
- Condensation in direct contact with a liquid at a temperature cooler than that of the saturated vapor.
- Homogeneous (or spontaneous) condensation as during the formation of a fog.[4]
References
- ↑ Eduardo Cao (2009). Heat Transfer in Process Engineering, 1st Edition. McGraw-Hill. ISBN 0-07-162408-2.
- ↑ G.S. Sawhney (2008). Heat and Mass Transfer. I.K. International Publishing House. ISBN 81-906942-7-8.
- ↑ For a saturated liquid to boil, the heat of vaporization must be absorbed into the liquid. For a saturated vapor to condense, the latent heat of vaporization must be released from the vapor. When released by a condensing vapor, the heat of vaporization is sometimes referred to as the heat of condensation.
- ↑ Robert G. Fleagle and Joost A. Businger (1980). An Introduction to Atmospheric Physics, 2nd Edition. Academic Press. ISBN 0-12-260355-9.