Elapsed time for air supply

[seanhkim]

I wonder how long it takes from when sensing a change in air pressure untill when increased air volume blows out of the supply vent.

Let's say I have an air pressure sensor dectecting a change of air pressure. Sensor reading is under requirement such that I need more makeup air. Signal containing the information about sensor reading goes through cables and reaches the controller. Controller calculates (maybe PID?) how much air volume is needed and send actuation signal to pnuematic actuator. The supply fan speed gets higher and the increased air is provided through a supply vent.

It should depend on what kind of HVAC system you have. But I'm just curious "how long" would be an average for high-end DDC system (usually used in hospitals and labs)

 

[marcoh]

Good question, I have been asking similar questions trying to figure out an issue in very slow response times in an existing system.

Seems like it very much depends on system architecture, where the data goes, and where the processing occurs. If the signal go to a local DDC outstation, is processed in that outstation, and that outstation controls the fan (and the VSD settings are correct) system performance should be good! If the data has to go back a head-end, and find its way through the whole DDC network, performance may be slowed dramatically!