What is the commonly used term for the tank in a freshwater cooling circuit?

The term "expansion tank" is commonly used in freshwater cooling circuits to refer to the tank that accommodates the expansion of the coolant as it heats up. This is crucial because liquids can expand when warmed, and without a designated area for this expansion, pressure could rise excessively within the cooling system, potentially causing damage or malfunction.

The expansion tank also serves to maintain a consistent pressure within the system and can help to ensure that any air trapped in the system is released, allowing for optimal cooling efficiency as water circulates. This function is particularly important in marine engines, where the freshwater cooling system is pivotal for maintaining safe operating temperatures.

In contrast, terms like "cooling reservoir," "water chamber," and "fluid storage container" are less specific and do not capture the unique role of managing thermal expansion and pressure that an expansion tank performs in the system.