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.
1 Plenum chamber, a chamber intended to contain air, gas, or liquid at positive pressure. 2  Plenism, or Horror vacui (physics) the concept that nature abhors a vacuum.3  Plenum (meeting) , a meeting of a deliberative assembly in which all members are present; contrast with quorum.lenum may refer to: 1  Plenum chamber, a chamber intended to contain air, gas, or liquid at positive pressure. 2  Plenism, or Horror vacui (physics) the concept that nature abhors a vacuum.