Dual duct system ESP calculation

[odelgado]

Hello everyone,

I'm sorry for doing this but I have a really novice question. I recently moved from a cooling only climate location to the US. Now I'm working with both cooling and heating systems. I have a doubt when calculating fan external static pressure for dual duct systems. Do I assume that in the worst case scenario all the airflow will be travelling through only one of the decks (e.g. summer or winter) or do I assume flow on both decks at any one point? I'm calculating the ESP from existing drawings so I don't have load calcs to know the peak load of the building, just what I'm seeing in the schedules and floor plans.

Thanks for any help you might provide.

 

[lukaiENG]

Take a look at where the outdoor ventilation comes into the building. I have a dual duct VAV system where all the OA comes in via the cooling unit and therefore it will have to run year round.
Also, you may need to run the cooling unit if there are any spaces which would require cooling year round - internal spaces with high heat loads (kitchens, IDFs, etc)