Dear all,
I am working on a?manufacturing project in which the system sizing and operation is different than the conventional practice.
?A lot of spaces have high infiltration rate, pressure requirements as well. The supply air for a particular zone is sized based on the air changes per hour. Therefore the supply air value is higher than?the dehumidified air quantity?what we get in the heat load calculations.??When it comes to cooling coil sizing, the coil is sized based on heat load calculations. Now we have a high capacity fan and a low capacity cooling coil.?The supply air quantity calculated from the heat load?(dehumidified air quantity)?will pass through the cooling coil and the rest of the air quantity bypasses the cooling coil. Finally the entire air quantity mixes and reaches the zone. Fresh air will be supplied through a Make up air unit.?The zone has infiltration, exfiltration to ensure the pressure is maintained.??In this scenario, we are getting high unmet hours because of high air flow rate.??I have modeled the infiltration ACPH, infiltration flow for each space in the "Internal loads" tab.The AHU fan is modeled with a high CFM. The issue is modeling the cooling coil as it is not cooling the entire supply air.Also, i tried modeling exfiltration as exhaust in each zone. However, the output reports (SV-A) show the Outside air quantity as outside air + exhaust air which is not the right value??Please let me know how to model these kind of systems. Any workaround available? This project is going for LEED submission.
Thank you.
Regards,Rathnashree