Humidity variation and condensation inside vented LED light enclosures

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LED lights have become extremely popular for exterior lighting of buildings due to their energy efficiency and**long life. GVA Lighting is a company based in Mississauga, Ontario that specializes in design and**manufacturing of innovative, high-end, solid state lighting systems. Their range of products includes outdoor**fixtures for illuminating building facades, bridges, retail stores and landscapes. The LEDs are in a sealed**plastic enclosure and when they are switched on the air temperature inside rises to 30°C above ambient. To**avoid high air pressure inside the fixture, which can lead to failure of the plastic enclosure, a small vent hole is**provided through which air can escape. The protective vent contains a microporous membrane that allows air**and water vapor to pass through while blocking water droplets and solid particles. However, since water vapor**can pass through the membrane, it is possible for enough moisture to build up so that its concentration exceeds**the dew point and it begins to condense. The accumulation of liquid water on the electronics inside the LED**light would cause catastrophic failure. The University of Toronto, in collaboration with GVA Lighting,**proposes to develop a computer program that can predict the variation of humidity inside the enclosure when it**is exposed to a given variation of external air temperature and humidity. The program will forecast condition**that may lead to moisture condensing inside the enclosure. Experiments will be done to determine the rate at**which water vapor diffuses through the vent.