History of the Natural Gas Heat Exchanger

If you have ever had a gas furnace, you are likely aware of the costliest repair on these units; the heat exchanger.  The heat exchanger of a furnace is a series of metal tubes between the combustion chamber and the blower in your furnace.  When the furnace burns natural gas, its exhaust by-products enter and travel through the primary heat exchanger.  The hot flue gas heats the metal as the gas makes its way to the exhaust outlet.  During this process, the air blows over the hot metal tubes and warms it before it travels through the ductwork and is distributed to rooms in your home.  It’s an ingenious method and we can thank the basic idea of this technology to an African American woman named Alice H. Parker who filed the first version of this idea as patent no. 1,325,905 on December 23, 1919.

During this time, not long after Carrier filed the first patent for the air conditioner, houses were using wood or coal-burning stoves and fireplaces to heat homes.  This produced smoke, soot, and ash so natural gas would have been a much cleaner burning fuel in the modern home with much less danger of fire if left unattended.

There is little known of Alice Parker’s personal life, and no photos of her that have surfaced, but she left her mark on this world and our industry forever; this basic technology is still used in modern heat exchangers and gas furnaces all over the world.

We salute you, Alice, for making use of a new heating source and a system of delivery that keeps us warm even today!  I only wish I could have interviewed her in person for this write-up; this is one woman who is going on my list of people I want to have coffee and conversations with someday.  Here are a couple of Alice’s patent drawings.  Enjoy.