[EnergyPlus_Support] Multiple chillers

["beyangj" <beyangj@xxxxxxxxxxx>]

Dear all,

I have some questions about the model of multiple chillers. There are
four water-cooled centrifugal chillers in the model, and their
capacity are the same. The chillers are controlled as SEQUENTIAL.

The first question is what's the relationship between  Plant Loop
Cooling Demand [W] and Chiller Evap Heat Trans Rate [W]? When I change
the reference capacity in Chiller:Electric:EIR, the Plant Loop Cooling
Demand[W] also changed, why this happened?


The second question is that the Reference Leaving Chilled Water
Temperature is set as 7¡æ,  and Leaving Chilled Water Lower Temperature
Limit is set as  5¡æ. But in the outputs, the Chiller Evap Water Outlet
Temp[C] is 5¡æ in all outdoor conditions, why the Chiller Evap Water
Outlet Temp[C] is  not 7¡æ as expected?

When the cooling capacity of three chillers satisfied the cooling
demand, but all the 4 chillers operated, and all the chiller operated
on low part load ratio, even all less than 0.3,  and Chiller Evap Heat
Trans Rate [W] of the first three chillers are the same, why no
chillers can operate at full load capacity? And why the fourth chiller
operates even there is no need for it to operate?  If three chillers
can provide enough cooling capacity, they can operate at even load
sharing without operating the 4th chiller? 


Thanks in advance.


Young
 



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