System Node Temperature and Mass flow rate doesn't meet setpoint schedule

asked 2020-04-29 03:51:56 -0500

Selma Inger's avatar

updated 2020-04-29 09:21:21 -0500

We have customized a refrigerant circulation system which eliminates heat from room to the chiller unit for data center. We designed the draft of system and it's loop by Designbuilder. Since Designbuilder has no component about ITE(i.e. CPU Server), now we uses Energyplus to get the detail data according to variables' changing pattern.

For the refrigerant circulation system, supply side is connected to chiller's demand side through fluid to fluid heat exchanger and demand side of refrigerant circulation system is connected to supply side of Air Loop which is cooling coil.

The load is ITE Load.

What I want to see from this system is the Indoor air temperature which varies by mass flow rate of refrigerant. On the process of setting mass flow rate, the problem is explained below.

1) I tried to set "Pump flow rate schedule" for refrigerant circulation's pump but it doesn't work. we find out that System node mass flow rate and temperature doesn't meet Mass flow rate and Temp. setpoint.

especially, if the mass flow rate setpoint to "Pump flow rate schedule" get below some value, simulation has FATAL errors. if the mass flow rate setpoint exceed a certain value, node mass flow doesn't keep linear(or constant) trend and fluctuates.

we used pump flow rate schedule, but it doesn't satisfy Pump mass flow rate schedule. also we used EMS. it doesn't work, too. How can we make system node flow rate constant for our customized system?

2) I would like to see the temperature variation which is caused by refrigerant mass flow rate. At this point, the indoor temperature must not include setpoint manager, but without setpoint manager, simulation meets an error.

Is there no way to simulate without setpoint Temperature manager?

thanks to you replies.

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