HVAC question
HVAC question
(OP)
Hi,
I am designing a HVAC system for an equipment room that houses a large electrical apparatus. The load in the room can vary from 10,000Btu/h to 85000Btu/h. The room area is 1345ft^2. Should I use CAV or VAV box?
I am designing a HVAC system for an equipment room that houses a large electrical apparatus. The load in the room can vary from 10,000Btu/h to 85000Btu/h. The room area is 1345ft^2. Should I use CAV or VAV box?





RE: HVAC question
RE: HVAC question
RE: HVAC question
can you be more specific about what equipment you have? ordinary electrical equipment can sustain much larger temperature range, while server rooms are something completely different.
it is rarely the case that common all-space cooling will be acceptable for electrical rooms - you either need heat rejection by ventilation or close control system, or at least separate cooling system as it is quite possible that cooling might be needed when other spaces are in heating mode.
RE: HVAC question
Have the min VAV setting as low as that VAV device can take. If it can do a 10:1 turn-down, ~400 cfm minimum. You can use 0 as a minimum, but understand that there are control limitations (meaning large fluctuations) with large VAV devices controlling in low ranges...
RE: HVAC question
RE: HVAC question
RE: HVAC question
VAV does not make sense in such an application. Variable load or not. The load is just too small to warrant the cost of VSD's, VAV boxes and Controls associated with it.
The space is 1400 SF housing large electrical equipment (one would understand swith gear or transformer). Using two small AC units CV (split system or CHW) along with an exhaust fan for winter air-side economizer will do just fine.
RE: HVAC question
RE: HVAC question
Is outdoor air out of the question? Fan sized for 9000 CFM w 9 deg delta. Turn fan on, when T above 90 degF, turn off when below 80 degF.
If not, is the WSHP recirculating and sized for 85 MBH? Then your all set.
Are you getting ari from another air ahndling unit? And that is why you ask for CAV vs VAV? If the rest oif the system is VAV, keep VAV. But it seems like a waste of energy for an electrical room.
knowledge is power
RE: HVAC question
Outdoor air is not acceptable, there is a coal plant close to the building.
RE: HVAC question
can you explain about the cooling system you mentioned above in details.
- does this cooling system serves only the electrical room or entire building,
- how come you can not use outside air because of a coal plant close to the room, there should be a clearances between buildings, what about people who works in the coal plant.
- are you going to use WSHP or it is already there.
- is there a people in the electrical room or just machines
- is it homework
RE: HVAC question