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E+ Equipment in Series on branch or equipment outside of splitter/mixer

asked 2017-09-20 18:36:18 -0500

When you put equipment in Series on a single branch, is flow allowed even if one equipment isn't on? I'd tend to say yes, but I'd like confirmation.

Does it flows through the off equipment if it's "passive" or magically bypasses it (in the case of storage tank or HX:FluidToFluid in uncontrolled mode for example)?

What happens if you put the equipment for example on the supply side of the plant loop, but after the mixer (right before the supply outlet node for example)? And on the demand side, right before the demand outlet node? (I've had problems before when I've tried strange stuff like that).

Example cases:

  • A Boiler:HotWater then a HeatExchanger:FluidToFluid
  • A Chiller:Electric:EIR then a WaterHeater:Mixed connected to another Source Side loop
  • A Chiller:Electric:EIR then a ThermalStorage:ChilledWater:Stratified (as in Plant application example 2)
  • A HeatExchanger:FluidToFluid placed on the supply side right before the Supply outlet node
  • A HeatExchanger:FluidToFluid placed on the demand side right before the Demand outlet node
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answered 2017-10-17 16:32:38 -0500

updated 2017-10-17 16:33:05 -0500

Everything I see in code implies series equipment will allow flow when the component is off if that component is in series with another that requires flow. For example this code in the boiler uses the water flow rate at the boiler water inlet node if the boiler is off and is in series with another component. If that flow rate is 0 then both will be off, otherwise water will flow through both and one component will (should?) be on. This code is at the beginning of the boiler performance calculation and as the comment states, will allow a non-zero flow rate when the boiler is off.

//If the specified load is 0.0 or the boiler should not run then we leave this subroutine.
// Before leaving, if the component control is SERIESACTIVE we set the component flow
// to inlet flow so that flow resolver will not shut down the branch
if ( MyLoad <= 0.0 || ! RunFlag ) {
    if ( EquipFlowCtrl == ControlType_SeriesActive )BoilerMassFlowRate = Node( BoilerInletNode ).MassFlowRate;
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Asked: 2017-09-20 18:36:18 -0500

Seen: 271 times

Last updated: Oct 17 '17