Heat transfer that occurs primarily by conduction is used for which type of process?

The correct answer is immersion. Immersion processes involve a material or substance being fully submerged in a fluid or medium, allowing for efficient heat exchange primarily through conduction. In an immersion setup, the heat is transferred directly through physical contact between the heated object and the fluid, making conduction the dominant mode of heat transfer.

This method is particularly effective in applications where uniform heating or cooling is required, as the entire surface area of the immersed object can effectively engage with the surrounding fluid, facilitating optimal heat transfer. Understanding the principles of conduction is critical in these scenarios, especially for refrigeration engineers who must ensure efficiency and effectiveness in their systems.

Indirect contact methods, while related to heat exchange processes, typically imply that the substance does not come directly into contact with the heating or cooling medium, which means conduction is not the primary mode of heat transfer. Similarly, air blast processes rely more on convection than conduction, and absorbers are associated with different mechanisms of heat transfer, particularly involving evaporation and condensation. Therefore, immersion stands out as the most appropriate answer for processes that utilize conduction extensively.