Honeywell AUTOMATIC CONTROL Engineering Manual page 270

AIR HANDLING SYSTEM CONTROL APPLICATIONS
PSYCHROMETRIC ASPECTS
In the following chart it is assumed that:
1. Outdoor air condition is 95°F DB and 79°F WB.
2. RA condition is 75°F DB and 57.5°F WB.
3. Coil leaving air temperature 50°F.
4. 80% OA.
2 COOL
SPACE LOAD
3
COIL DISCHARGE
50°F DB, 47°F WB
ENGINEERING CMANUAL OF AUTOMATION CONTROL
OA 95°F DB,
79°F WB
1
81.4°F DB
RA 78°F DB,
4
57.5°F WB
C2578-1
The following results are obtained:
Item
No. Explanation
1. RA mixes with 20 percent (minimum
position) outdoor air to obtain mixed air
condition.
2. Air entering the coil is cooled along a line of
constant moisture content until saturation is
approached. Near saturation the moisture
content is reduced as the air is cooled. This
process involves both latent and sensible
cooling.
3. Mixed air is cooled and dehumidified by
cooling coil to obtain cooling coil leaving air
condition.
4. Reheat coils and/or space heats air to 75°F
DB and 57.5°F WB.
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