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.
A chiller is a heat-transfer device that uses mechanical. refrigeration to remove heat from a process load and. transfers the heat to the environment. Chillers are used by. plastics processors when they need a lower process fluid. temperature than a simpler system, such as an evaporative. cooling tower, can provide.