Question 481General Subjects - Assistant Engineer

70% to pass

Referring to the illustrated psychrometric chart, suppose during the cooling season that air passes over a cooling coil with a mean surface temperature above the dew point temperature, and this results in sensible heat loss with no change in moisture content. What statement represents the direction of the air conditioning process line? Illustration GS-RA-22

Diagram for USCG General Subjects Assistant: Referring to the illustrated psychrometric chart, suppose during the cooling...
AThe air conditioning process line is vertical with the coil outlet below the coil inlet.
BThe air conditioning process line is horizontal with the coil outlet to the left of the coil inlet.
CThe air conditioning process line is vertical with the coil outlet above the coil inlet.
DThe air conditioning process line is horizontal with the coil outlet to the right of the coil inlet.
AI Explanation

The correct answer is B) The air conditioning process line is horizontal with the coil outlet to the left of the coil inlet. When air passes over a cooling coil with a mean surface temperature above the dew point temperature, it results in sensible heat loss with no change in moisture content. This means the air is cooled without any condensation occurring, and the process line on the psychrometric chart will be horizontal, moving from right to left as the air is cooled. The other options are incorrect because A) and C) describe a vertical process line, which would indicate a change in moisture content, and D) describes a horizontal process line moving from left to right, which is the opposite of what occurs in this scenario.

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