June 5, 2013

Natural Ventilation And Fog Increase Cooling Efficiency

For greenhouse ventilation, two main methods are used — mechanical and natural. Mechanical ventilation includes fan-and-pad systems, which are a type of evaporative cooling system. Fan-and-pad systems cool air by passing outside air through a wet pad, lowering the temperature and humidifying the greenhouse. This type of system works best in hotter, drier climates, because the capacity for cooling with a fan-and-pad system is very limited in humid climates. University of Arizona associate professor Murat Kacira says a drawback of using a fan-and-pad type system is that it requires a lot of energy and water. “Water is needed for the pad system, and energy is needed to run the pump for water circulation over the pad as well as the energy to run the exhaust fans,” Kacira says. “Water is a precious resource with limited availability, especially in arid and semi-arid regions. “Another issue is there can be a temperature […]

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