Chiller Plant Electrical Demand Load 1

[Reesh14]

I have estimated a connected load of about 4,000 KVA for a chiller plant (serving several other buildings) design. I simply used the voltage (460V) and amperage of all the equipment (chillers, cooling towers, and pumps) and calculated the total KVA load. Also included 10 KVA for lights and receptacles.

Is there a diversity I can apply to my total KVA load in order to determine the demand load? Typically we use 80% for HVAC equipment but I do not see this in any code books. I have also seen 60% used.

I was told to size the incoming feeders and switchboard for all the HVAC equipment (no redundancy). If the 80% or 60% is a rule of thumb based on the fact that not all the equipment runs at the same time, then I might not be able to take it into account in this case.

Thank you.

 

[rbulsara]

There is no rule. You really need to have a good handle on as to how the plant is going to operate, especially during the design degree days and what type of design margins were included by your mechanical engineer.

You need to consult your mechanical engineer and also senior level electrical and mechanical engineer responsible for the project.

If in doubt, err on the conservative side.


Rafiq Bulsara

http://www.srengineersct.com