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TRG-TRC001-EN 49
period six
Psychrometric Analyses
notes
This supply air E mixes with room air along the part-load 0.70 SHR line, arriving
at the resulting new room conditions A’. While the quantity and temperature of
supply air are suitable to absorb the room’s sensible heat gain, they are unable
to completely absorb the latent heat gain. The result is a shift in room
conditions from the design point A to 78°F DB, 58% RH (A’).
The final method of part-load control we will analyze is to vary the supply
airflow to the room.
Let’s look at the same example again, this time using a simple variable-air-
volume (VAV) system. This system responds to part-load conditions by
supplying a variable quantity of constant-temperature air. At full load, this
system looks the same on the psychrometric chart as the constant-volume
system—it supplies 3,430 cfm of 56.5°F air to the room.
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