Condensation forming in the low pressure zone above the wing of an aircraft due toadiabatic expansion
Condensation is the change of thestate of matter from thegas phase into theliquid phase, and is the reverse ofvaporization. The word most often refers to thewater cycle.[1] It can also be defined as the change in the state of water vapor to liquid water when in contact with a liquid or solid surface orcloud condensation nuclei within theatmosphere. When the transition happens from the gaseous phase into the solid phase directly, the change is calleddeposition.
Condensation is initiated by the formation ofatomic/molecular clusters of that species within its gaseous volume—likerain drop orsnow flake formation withinclouds—or at the contact between such gaseous phase and a liquid or solid surface. Inclouds, this can be catalyzed bywater-nucleating proteins, produced by atmospheric microbes, which are capable of binding gaseous or liquid water molecules.[2]
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 asevaporation.[1]
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 assublimation.
Condensation commonly occurs when avapor is cooled and/or compressed to itssaturation limit 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".
Condensation on the outside of a window, due to it being in front of the sea which regularly produces moistsea spray.
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.
Condensation is a crucial component ofdistillation, 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 asair wells andfog fences. Such systems can often be used to retain soil moisture in areas where activedesertification 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.[3]
It is also a crucial process in forming particle tracks in acloud 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,[4] thermal management,[5] refrigeration,[6] and air conditioning.[7]
Condensation in buildingconstruction is an unwantedphenomenon as it may causedampness,mold health issues,woodrot,corrosion, weakening of mortar and masonry walls, and energy penalties due to increasedheat 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.[8] The amount of water vapor that can be stored in the air can be increased simply by increasing the temperature.[8] 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.
^Q&A: Microchannel air-cooled condenser; Heatcraft Worldwide Refrigeration; April 2011;"Archived copy"(PDF).Archived(PDF) from the original on 2012-04-17. Retrieved2013-02-20.{{cite web}}: CS1 maint: archived copy as title (link)
