Condensation is the change of the state of matter from the gas into the liquid, and is the reverse of vaporization. The word most often refers to the water cycle.
Initiation
Condensation is initiated by the formation of atomic/molecular clusters of that species within its gaseous volume—like
rain drop or
snow flake formation within
—or at the contact between such gaseous phase and a liquid or solid surface. In
clouds, this can be catalyzed by water-nucleating proteins, produced by atmospheric microbes, which are capable of binding gaseous or liquid water molecules.
Reversibility scenarios
A few distinct reversibility scenarios emerge here with respect to the nature of the surface.
-
absorption into the surface of a liquid (either of the same substance or one of its solvents)—is reversible as evaporation.
-
adsorption (as dew droplets) onto solid surface at pressures and temperatures higher than the species' triple point—also reversible as evaporation.
-
adsorption onto solid surface (as supplemental layers of solid) at pressures and temperatures lower than the species' triple point—is reversible as sublimation.
Most common scenarios
Condensation commonly occurs when a
vapor is cooled and/or compressed to its
dew point when the molecular density in the gas phase reaches its maximal threshold. Vapor cooling and compressing equipment that collects condensed liquids is called a "condenser".
Measurement
Psychrometry measures the rates of condensation through evaporation into the air moisture at various atmospheric pressures and temperatures. Water is the product of its vapor condensation—condensation is the process of such phase conversion.
Applications of condensation
Condensation is a crucial component of
distillation, an important laboratory and industrial chemistry application.
Because condensation is a naturally occurring phenomenon, it can often be used to generate water in large quantities for human use. Many structures are made solely for the purpose of collecting water from condensation, such as air wells and . Such systems can often be used to retain soil moisture in areas where active desertification is occurring—so much so that some organizations educate people living in affected areas about water condensers to help them deal effectively with the situation.[ FogQuest - Fog Collection / Water Harvesting Projects - Welcome ]
It is also a crucial process in forming particle tracks in a cloud chamber. In this case, ions produced by an incident particle act as nucleation centers for the condensation of the vapor producing the visible "cloud" trails.
Commercial applications of condensation, by consumers as well as industry, include power generation, water desalination,[White, F.M. 'Heat and Mass Transfer' © 1988 Addison-Wesley Publishing Co. pp. 602–604] refrigeration,[Q&A: Microchannel air-cooled condenser; Heatcraft Worldwide Refrigeration; April 2011; ] and air conditioning.
Biological adaptation
Numerous living beings use water made accessible by condensation. A few examples of these are the
thorny devil, the
of the
coast, and the coast redwoods of the West Coast of the United States.
Condensation in building construction
Condensation in building
construction is an unwanted
phenomenon as it may cause dampness, mold health issues,
wood Dry rot,
corrosion, weakening of mortar and masonry walls, and energy penalties due to increased
heat transfer. To alleviate these issues, the indoor air humidity needs to be lowered, or air ventilation in the building needs to be improved. This can be done in a number of ways, for example opening windows, turning on extractor fans, using dehumidifiers, drying clothes outside and covering pots and pans whilst cooking. Air conditioning or ventilation systems can be installed that help remove moisture from the air, and move air throughout a building.
The amount of water vapor that can be stored in the air can be increased simply by increasing the temperature.
However, this can be a double edged sword as most condensation in the home occurs when warm, moisture heavy air comes into contact with a cool surface. As the air is cooled, it can no longer hold as much water vapor. This leads to deposition of water on the cool surface. This is very apparent when central heating is used in combination with single glazed windows in winter.
Interstructure condensation may be caused by , insufficient or lacking insulation, damp proofing or insulated glazing.
Table
See also
- Sources
