condensation

Examples of condensation in the following topics:

• The Evaporating Atmosphere

  • At equilibrium, evaporation and condensation processes exactly balance and there is no net change in the volume of either phase.
  • Likewise, every once in a while a vapor molecule collides with the liquid surface and condenses into the liquid.
  • At equilibrium, evaporation and condensation processes exactly balance and there is no net change in the volume of either phase.
  • Collisions between water molecules in the atmosphere allows some to condense and some to remain in vapor.

• Heat Pumps and Refrigerators

  • The basic components of a heat pump in are a condenser, an expansion valve, an evaporator and a compressor .
  • The electrically driven compressor (work input W) raises the temperature and pressure of the gas and forces it into the condenser coils that are inside the heated space.
  • Because the temperature of the gas is higher than the temperature inside the room, heat transfer to the room occurs and the gas condenses to a liquid.
  • (In a cooling cycle, the evaporator and condenser coils exchange roles and the flow direction of the fluid is reversed. )
  • A simple heat pump has four basic components: (1) condenser, (2) expansion valve, (3) evaporator, and (4) compressor.

• Latent Heat

  • Conversely, energy is released during freezing and condensation, usually in the form of thermal energy.
  • Note that melting and vaporization are endothermic processes in that they absorb or require energy, while freezing and condensation are exothermic process as they release energy.
  • The same energy must be removed for condensation to take place.

• Convection

  • If the water vapor condenses in liquid droplets as clouds form, heat is released in the atmosphere (this heat release is latent heat)  .
  • Water vapor carried in by convection condenses, releasing tremendous amounts of energy, and this energy allows air to become more buoyant (warmer than its surroundings) and rise.
  • As the air continues to rise, more condensation occurs, which in turn drives the cloud even higher.

• Humidity, Evaporation, and Boiling

  • At the dew point temperature, relative humidity is 100%, and fog may result from the condensation of water droplets if they are small enough to stay in suspension.
  • If a lid is placed over the container, as in (b), evaporation continues, increasing the pressure, until sufficient vapor has built up for condensation to balance evaporation.

• Evaporation

  • (b) If the container is sealed, evaporation will continue until there is enough vapor density for the condensation rate to equal the evaporation rate.

• Linear Expansion

  • Typical inter-particle potential in condensed matter (such as solid or liquid).