Heaters located just under the interior faces of a refrigerators keep this from occurring.

Heaters located just under the interior faces of a refrigerators keep this from occurring.

• A. Frost buildup
• B. Sweating
• C. Condensation
• D. Ice formation

Answer: (B)

The situation tests understanding of condensation control on cold surfaces. When humid air comes into contact with a surface that's cooler than the air’s dew point, water condenses as liquid on that surface—that is sweating. Placing heaters right under the interior faces raises the inner wall temperature just enough so it stays above the dew point, preventing liquid moisture from forming there. So the heaters stop sweating by keeping the surface from reaching the temperature at which condensation occurs. Frost buildup and ice formation require the surface to be at or below freezing, which isn’t the condition being addressed by these heaters. Condensation is the general process, but sweating refers specifically to moisture condensing on these interior, cooler surfaces, which is what the heating prevents.

The situation tests understanding of condensation control on cold surfaces. When humid air comes into contact with a surface that's cooler than the air’s dew point, water condenses as liquid on that surface—that is sweating. Placing heaters right under the interior faces raises the inner wall temperature just enough so it stays above the dew point, preventing liquid moisture from forming there. So the heaters stop sweating by keeping the surface from reaching the temperature at which condensation occurs.

Frost buildup and ice formation require the surface to be at or below freezing, which isn’t the condition being addressed by these heaters. Condensation is the general process, but sweating refers specifically to moisture condensing on these interior, cooler surfaces, which is what the heating prevents.