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[EnergyPlus_Support] Merging zones having FCUs (Merging FCUs)



Hi,
For one case, I tried to merge actual zones into larger thermal zones. Now, I have to model FCUs, using TemplateHVAC:Zone:FanCoil objects, in such a way that I put one FCU in each zone that must represent 4, 5 or even 11 real FCUs for example. I used the following approach:
1. I used the formula from DesignBuilder website (http://www.designbuilder.co.uk/programhelp/fans.htm) to find Fan Delta Pressure:
Delta P = 1000 * SFP * Fan total efficiency (SFP: Specific Fan Power [W/(L/s)]
I calculated each real FCU's Fan Delta P and added them up to find the equivalent FCU's fan Delta P.
For example: 
I have 4 FCU's one for each of 4 guest rooms that I merged into one large room for simplification, the actual HVAC schedules give the following:

FCU No.      Power [kW]             Air Flow [L/s]
==================================================
1              0.3                       160
2              0.3                       145
3              0.3                       145
4              0.3                       145


Eqv. Delta P= 1000*(300[W]/160[L/s]+3*300[W]/145[L/s])*0.7=5657.33[Pa]


2. I found the equivalent FCU's airflow rate by adding the real FCUs' flow rates:
Eqv. Flow Rate=160+3*145=595[L/s]


I used the above values in the HVACTemplate:Zone:FanCoil object for the corresponding zone. The results were that the equivalent FCU's power calculated is 5 times larger (about 6[kW]) than actual component-FCUs' power when added up: