Expansion Tanks for Heat Transfer Systems

An expansion tank is an essential component to all heat transfer systems. Heat transfer fluids expand with an increase in temperature. Expansion tanks allow for and contain the increase in volume due to temperature. In addition, cold expansion tanks provide a “seal” on the system reducing oxidation of the fluid. They also add to the net positive suction head (NPSH) on the inlet to the pump.

Expansion tanks should be sized based on the amount of thermal expansion of the heat transfer fluid in the system. The actual size of the tank should be at least double the anticipated increase in fluid volume. Tank capacity should be increased if the process piping is extensive and contains a significant volume of fluid. The following tables indicate the typical tank sizes for most systems.

• Heat Transfer Systems Design Guide
• Heat Transfer Expansion Tanks
• Packaged Systems Overview