The international airports in Pennsylvania are Lehigh International Airport at Allentown, Erie International Airport at Erie, Harrisburg International Airport at Harrisburg, Philadelphia International Airport at Philadelphia,
Electric Plenum Heaters. A plenum heater is an electric resistance heating device that is installed in the plenum, which is the spot in the ductwork system where ducting and furnace join. Air is heated as it flows across electric elements and then is distributed through the existing ductwork.
plenum chamber. A component of a jet engine designed to hold air at a pressure slightly higher than that of the surrounding air. Plenum chambers stabilize the pressure of the air before it enters the compressor.n enclosed space in which a plenum condition exists; air is forced into it for slow distribution through ducts.