I'm an HVACR guy by trade but I am stumped as to why every time I walk in to Home Depot and walk around, I am invariably blasted by a jet of air coming from a large ceiling diffuser in its own "box" or plenum (no ducting that I can see). I'm almost positive that there is a high-velocity centrifugal (or axial) fan in each of these.
But why?
If these are just straight fans, wouldn't it have been wiser just to utilize the economizer that is installed on 99% of packaged rooftop units? They already have the ductwork for HVAC in the store. It just seems redundant to have giant, independent fans blow a blast of air into the space.
There would be no way that these are centralized. In fact I heard the motor spool up--as clear as can be--as I was standing right under one. You never really hear the blower motor on a centralized system, whether the system is heating, air conditioning or ventilation.
But why?
If these are just straight fans, wouldn't it have been wiser just to utilize the economizer that is installed on 99% of packaged rooftop units? They already have the ductwork for HVAC in the store. It just seems redundant to have giant, independent fans blow a blast of air into the space.
There would be no way that these are centralized. In fact I heard the motor spool up--as clear as can be--as I was standing right under one. You never really hear the blower motor on a centralized system, whether the system is heating, air conditioning or ventilation.