Engineering Manual o.. - HVAC.Amickracing

AIR HANDLING SYSTEM CONTROL APPLICATIONSPSYCHROMETRIC ASPECTSIn the following chart it is assumed that:1. Outdoor air condition is 35°C DB and 26°C WB.2. RA condition is 24°C DB and 14.5°C WB.3. Coil leaving air temperature 10°C.4. 80% OA.2SPACE LOADCOOL3 4COIL DISCHARGE10°C DB, 8°C WB115.8°C DBRA 26°C DB,14°C WBOA 35°C DB,26°C WBThe following results are obtained:ItemNo.Explanation1. RA mixes with 20 percent (minimum position)outdoor air to obtain mixed air condition.2. Air entering the coil is cooled along a line ofconstant moisture content until saturation isapproached. Near saturation the moisture contentis reduced as the air is cooled. This processinvolves both latent and sensible cooling.3. Mixed air is cooled and dehumidified bycooling coil to obtain cooling coil leaving aircondition.4. Reheat coils and/or space heats air to 24°CDB and 14.5°C WB.C3266260ENGINEERING MANUAL OF AUTOMATIC CONTROL