How does fog work?

Fog systems provide outdoor cooling through evaporation. Evaporative cooling, or Thermal Dynamics, is a very simple process. Water requires energy to evaporate (600 calories of heat per gram of water.) As the fog evaporates, the energy exchange results in temperature reductions. The effectiveness of this process is dependent on the existing temperature and humidity. The effectiveness of the cooling process improves as the temperature rises (85 degrees F to 115 degrees F is ideal) and the humidity level drops (above 90% humidity - performance is marginal; 40% to 90% humidity - performance is good; below 40% humidity - performance is excellent). The expected temperature drop will vary depending on the climate conditions, but cooling up to 40 degrees F is achievable under ideal circumstances.

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