[EnergyPlus_Support] Re: Mass flow rate problems using energy plus 1.2.2

["patrik_789" <patrik_789@xxxxxxxx>]

Dear Mike,

sorry for the deleted response. The problem I described (Free 
cooling heat exchanger: hydronic) was not fixed.
I controlled my inputs another time and I didn't found any errors 
like node connection errors or branch errors.
After a few tests, I could point out the main problem: When I use 
two heat exchangers: hydronic: Free cooling- objects, the simulation 
crashed, because the calculated inlet mass flow rate for demand side 
splitter doesn't match with the outlet mass flow rate of the demand 
side splitter.
Furthermore the mass flow rate for the demand side splitter inlet 
calculated by energy plus was always the double of the mass flow 
rate on the demand side mixer outlet, which is the same mass flow 
rate as for the supply side splitter inlet.
It seems that there is a mass flow source somewhere in the supply 
side of the cooling loop, but this couldn't be (I could not 
understand where and why).
After this I started a simulation where only one of the condenser 
loops was connected with the cooling loop by a chiller and a heat 
exchanger: hydronic: Free cooling- object and the other condenser 
loop by a normal chiller.
The simulation didn't crash.
The resultant questions are:
 
1.	How many heat exchanger: hydronic: Free cooling- objects are 
allowed for each cooling loop
2.	Is there a controller for the mass flow rates or the load 
distribution for the heat exchanger: hydronic: Free cooling- object, 
because it could be that there are some problems with the load / 
mass flow distribution, when I use more then one free cooling object?

I have seen, that you asked if I have a bypass on the demand side of 
the cooling loop.
Yes there is a bypass on the demand side. I've tried a simulation 
without the bypass on the demand side, but the simulation crashed 
too.
I will upload the file to the file area for the case that you will 
have a look at it.

Attachments:
Heat_exchanger_free_cooling.zip

Best regards, 

Patrik 
  

    







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