What material are most heat exchangers in furnaces made from?

What material are most heat exchangers in furnaces made from?

• A. Aluminum.
• B. Copper.
• C. Steel.
• D. Plastic.

Answer: (C)

The key idea is that heat exchangers must endure hot, potentially corrosive combustion gases while staying strong and affordable. Steel provides the best balance: it can handle the high temperatures and pressure, resists the kind of thermal cycling that occurs with furnace operation, and is cost-effective for producing large exchanger surfaces. Copper conducts heat very well but is too soft and expensive for the thick walls and long life needed in furnace exhaust paths. Aluminum also conducts heat well but loses strength at high temperatures and isn’t as durable in the harsh furnace environment. Plastic cannot stand up to the heat of furnace exhaust at all. So, steel (often carbon steel or aluminized/stainless variants) is the typical material for furnace heat exchangers.

The key idea is that heat exchangers must endure hot, potentially corrosive combustion gases while staying strong and affordable. Steel provides the best balance: it can handle the high temperatures and pressure, resists the kind of thermal cycling that occurs with furnace operation, and is cost-effective for producing large exchanger surfaces. Copper conducts heat very well but is too soft and expensive for the thick walls and long life needed in furnace exhaust paths. Aluminum also conducts heat well but loses strength at high temperatures and isn’t as durable in the harsh furnace environment. Plastic cannot stand up to the heat of furnace exhaust at all. So, steel (often carbon steel or aluminized/stainless variants) is the typical material for furnace heat exchangers.