Referring to the illustrated psychrometric chart, suppose air at a dry-bulb temperature of 60F and a relative humidity of 52% passes over a heating coil, resulting in sensible heat gain, and the off-coil temperature is now 80F. What is off-coil relative humidity? GS-RA-22

Illustration GS-RA-22: the U.S. Coast Guard has not released this illustration.

Question

Referring to the illustrated psychrometric chart, suppose air at a dry-bulb temperature of 60F and a relative humidity of 52% passes over a heating coil, resulting in sensible heat gain, and the off-coil temperature is now 80F. What is off-coil relative humidity? GS-RA-22

Illustration GS-RA-22: the U.S. Coast Guard has not released this illustration.

Accepted Answer

Option B: 27%. Adding sensible heat without altering moisture content shifts the psychrometric state horizontally to the right along a constant humidity ratio line. Following this path to an 80F dry-bulb temperature results in a decreased relative humidity value of approximately 27%.