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[EnergyPlus_Support] Re: Hybrid boiler system system
Thank you for your insights!
I have modeled the boilers in parallel, since that is the actual and
common piping arrangement.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "mingming_zuo"
<mingming_zuo@...> wrote:
>
> It seems like two boilers located in series, if the heating load does
> not exceed the upper limit for the first stage boiler, the second
> stage boiler will not be used. So the second boiler does not start
> may indicate that the first boiler is enough to meet heating load.
My problem seems to be a misunderstanding of the HEATING LOAD RANGE
BASED OPERATION object. The arrangement I use, which I have shown
below, should turn on only one boiler when the load is less than
88,000 W. When the results are reported, though, and the load exceeds
the capacity of the first boiler, both boilers operate (which is
expected), but the first boiler is NOT operating at full capacity.
Since the first boiler has higher efficiency, I want it operating at
full capacity, with the second boiler meeting the remaining load.
PLANT OPERATION SCHEMES,
PlantOperationSchemeName PltOpernScheme_Htg,
KEY--Control Scheme 1 HEATING LOAD RANGE BASED OPERATION,
Control Scheme Name 1 HtgLdRngBasedOpern_1,
Control Scheme Schedule 1 SchCpct_AlwaysOn;
HEATING LOAD RANGE BASED OPERATION,
Name HtgLdRngBasedOpern_1,
Load Range Lower Limit 1 (W) 0,
Load Range Upper Limit 1 (W) 88000,
Priority Control Equip List Name 1 PltEquipList_Htg1,
Load Range Lower Limit 2 (W) 88001,
Load Range Upper Limit 2 (W) 2931000,
Priority Control Equip List Name 2 PltEquipList_Htg2;
PLANT EQUIPMENT LIST,
Equip List Name PltEquipList_Htg1,
KEY--Plant Equip 1 BOILER:SIMPLE,
Equip Name 1 Boiler_1;
PLANT EQUIPMENT LIST,
Equip List Name PltEquipList_Htg2,
KEY--Plant Equip 1 BOILER:SIMPLE,
Equip Name 1 Boiler_1,
KEY--Plant Equip 2 BOILER:SIMPLE,
Equip Name 2 Boiler_2;
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "JV Dirkes II"
> <jvd2pe@> wrote:
> >
> > Dear E+ Forum,
> >
> > I am modeling a "hybrid" boiler system, which uses a small high
> > efficiency condensing boiler as the first stage of heating, and a
> > larger, less efficient boiler as the second stage.
> >
> > I've manually sized the boiler capacities and boiler water flows. I
> > have also set the HEATING LOAD RANGE BASED OPERATION to define the
> > upper limit of the first stage as equal to the first boiler's
> capacity.
> >
> > However, the first boiler never reaches full capacity before the
> > second boiler starts operating.
> >
> > Have any of you modeled this system? Can you offer suggestions why
> the
> > first boiler is not loading fully?
> >
> > Thanks!
> >
>
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