What is a characteristic of a combination superheater?

A combination superheater is designed to enhance the efficiency of steam generation by utilizing both radiant and convection heating methods. Radiant superheaters take advantage of the fiery radiation from the furnace, allowing for the heating of water or steam in proximity to the heat source. In contrast, convection superheaters heat the steam through contact with hot gases circulating in the flue, capitalizing on the movement of hot exhaust.

By employing both configurations in series, a combination superheater efficiently utilizes the strengths of each type. The radiant section operates at higher temperatures where it can maximize heat absorption, while the convection section ensures that the steam remains superheated as it moves down the line, creating optimal temperature profiles for improved performance.

The other characteristics presented in the options do not align with the function and design of a combination superheater. It does not operate solely with radiant heat, as that would limit its ability to use the efficiencies gained from convection heating. Maintenance is indeed necessary for combination superheaters, as with any complex boiler component, to ensure operational reliability and safety. Lastly, while installation costs can vary based on design and requirements, a combination superheater typically involves more complex setup and materials than simpler designs, which may not result in the lowest installation costs.