Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
I assume you are autosizing the coils otherwise you could have specified the correct flow ratio. In the Sizing:Zone objects, the supply air temperature is specified which is used to determine the zone air flow rate. During sizing this supply air temperature, along with the zone temperature, is used to calculate a zone air flow rate given the zone load, for each time step. The air flow rate at the maximum load is used as the design load. These parameters are used to size the coil. If the Sizing:Zone supply air temperature is too high (i.e., close to the zone temperature) the zone air flow rate will also be high. A reasonable temperature difference for DX equipment is 11C so the supply air temperature should be around T = zone temp - 11 C.
