Hi mirza057,
I've used spot ventilation on manufacturing plant with equipment that has high heat load. It does not make sense to cool the entire area if you could isolate the heat source. I also do not see any problem in applying it to transformer rooms.
Regards,
Hi,
May I know if anyone has an idea or reference for criteria of designing/sizing distribution network for district cooling system?
Thank you in advance.
317069,
You are missing the point. The answer to your question is Yes. VAV rooftop unit does not necessarily mean it has a VAV box on the zone. Your example has VAV box which means it has multiple zone. If you would just spend time on analyzing the std. 62, for multiple zone system, your OA...
Hi 317069,
There are some conflict with your info.
"Drazen the question was: do we need to ensure minimum OA to a zone or it is enough to provide required OA (500 cfm in my example) to the system as a one zone"
First, you must use different approach on computing single zone and multiple zone...
Hi 317069,
ASHRAE has already considered this issue with VAV system by introducing the "system ventilation efficiency" as discussed by randomusername. This is at the system level and not on the zone level.
Hi 317069,
As pointed out by randomusername, regardless of SA requirement (full or minimum) the OA (as held constant) would mix with your RA at the AHU. A schematic of air balance would help.
Remember that your design requirements are :
Total gross capacity required = 368.7 MBh = 31 Tons
Total sensible capacity required = 259 MBh
The selected unit was :
370 MBh x 1.005 = 371.85 MBh
282 MBh x 1.014 = 285.95 MBh
which satisfies the requirements. The coil performance would "play...