Which of the following best describes a boiler's function in an industrial setting?

The primary function of a boiler in an industrial setting is to produce steam or hot water. Boilers achieve this by heating water using a controlled fuel source, which typically involves combustion of fuel, although other heating methods such as electric resistance or hot gases can also be employed. The steam generated by a boiler serves various critical roles, from providing heat for building spaces to powering turbines for electricity generation or facilitating various industrial processes where steam is a necessary component.

In contrast, the other options describe functions that are either not associated with a boiler at all or are secondary to its primary role. For instance, while cooling process fluids, storing thermal energy, and regulating feedwater quality are all important functions in an energy management system, they do not directly define the boiler's main purpose. Thus, the correct answer reflects the central and essential role that boilers play in the production of steam and hot water in industrial applications.