Multiplexing with VAV terminals

[iggleton]

I have several zones in my building served by different air handling units. So I create a few different multiplex zones to represent those areas, but the design airflow (in l/s) for the rooms within a single zone varies. I just have modelled one fan (in the AHU) going into the multiplex, so I have set the design flow rate for the AHU fan to the design flow rate of the room with the highest flow rate (l/s) in the multiplex. Is there a way to more accurately represent the flowrates of the different rooms in a single multiplex?

[farahghanem]

I am not sure I understood your question properly... here is what I gathered from what you said: "you have rooms which are served by more than one AHU, and have created a multiplex with each layer having the same room (which is being supplied by the multiple AHUs), and then you have a single fan at AHU system level going into the multiplex (the fan is not inside the multiplex)."

I do not think the best approach is to have the same room on multiple layers, I would presume this will confuse the software. Have you checked if the total supply air is the same as design (sum of all AHU supplies)?

Try combining the flow rates, fan powers, coil capacities of the multiple AHUs supplying a single zone and represent them in single components in your network. That should give you approximately the same energy consumption and flow rates.