I am trying to develop model based control for chilled water system using external interface. I checked the rdd file of my idf file and I couldn't get output for cooling tower fan air flow rate. I used auto-sized variable speed fan for the cooling tower and I couldn't also find the nominal capacity of my fan (kg/s) in the summary report. The only information I got is the air flow ratio. But I was wondering if there is anyway to find the actual flow or the nominal capacity of the cooling tower fan. I tried to output the "system node flow rate" by defining the " Outdoor Air Inlet Node Name" in the "Cooling Tower: VariableSpeed" object but the value is reading zero for the entire simulation period. The zero value for the air flow rate for the entire simulation period doesn't seem to be correct since the free convection heat rejection capacity of my cooling tower (0.125 of the nominal capacity) is less than actual heat rejection for most of the simulation period. I ll appreciate if some body can give me some idea to get the value of the above mentioned variables (cooling tower fan air flow rate or cooling tower fan air flow rate)
Regards,
korbaga