Re: [EnergyPlus_Support] Re: Plant temperatures are getting far too cold

On Thu, Aug 22, 2013 at 8:16 AM, Maria Sole <mariasole297@xxxxxxxxx> wrote:

Sorry but i don't understand which field i have to change to obtain a costant flow condition? Thanks

From: Edwin Lee <leeed2001@xxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Thursday, August 22, 2013 4:01 PM
Subject: Re: [EnergyPlus_Support] Re: Plant temperatures are getting far too cold

The vertical GLHE model has in the past encuntered some issues causing oscillation. Things to try:
Make sure your GLHE is sized appropriately for your situation. Don't just grab an object from the example file, as it may be completely wrong. If you change *some* of the parameters, the g-function will likely need to be re-generated.

Highly variable flow conditions can cause issues. As a first step, try to run your GLHE on a constant flow condition. If you need variable flow on your demand equipment then put in an uncontrolled common pipe.

Try these and see if they fix anything.

Edwin

On Thu, Aug 22, 2013 at 7:48 AM, energyplus_mimis <welma.pereira@xxxxxxxxx> wrote:

Do you have a boiler or other water heater in the plant loop? If there is one there the water should be heated as much as you set

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Maria Sole <mariasole297@...> wrote:
>
> I have already tried to change the CHW Loop Setpoint Manager but the severe error is always the same, i mean the outlet temperature is every time different but is always too low.
>
>
> ________________________________
> From: energyplus_mimis <welma.pereira@...>

> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Sent: Thursday, August 22, 2013 2:57 PM
> Subject: [EnergyPlus_Support] Re: Plant temperatures are getting far too cold
>
>
>
> Â
>
> It seems like your set point temperature for the plant loop is very low, check the temperature schedule in the SetpointManager:Scheduled
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "mariasole297" <mariasole297@> wrote:
> >
> > Hi,
> > i'm tring to simulate the following heating and cooling system:
> >
> > Groung heat exchanger+ heat pump+ heating/cooling floor
> >
> > When I start the simulation E+ always returns this sever error.
> >
> > ** Severe ** Plant temperatures are getting far too cold, check controls and relative loads and capacities
> > ** ~~~ ** Environment=SENZA TITOLO, at Simulation time=05/08 19:16 - 19:19
> > ** ~~~ ** PlantLoop Name (SupplySide)= CHW LOOP
> > ** ~~~ ** PlantLoop Setpoint Temperature=6.7 {C}
> > ** ~~~ ** PlantLoop Inlet Node (SupplySide) does not have a Setpoint.
> > ** ~~~ ** PlantLoop Inlet Node (DemandSide) does not have a Setpoint.
> > ** ~~~ ** PlantLoop Outlet Node (SupplySide) has a Setpoint.
> > ** ~~~ ** PlantLoop Outlet Node (DemandSide) does not have a Setpoint.
> > ** ~~~ ** PlantLoop Outlet Node (SupplySide) "CHW LOOP SUPPLY SIDE OUTLET" has temperature=-105.3 {C}
> > ** ~~~ ** PlantLoop Inlet Node (SupplySide) "CHW LOOP SUPPLY SIDE INLET" has temperature=7.1 {C}
> > ** ~~~ ** PlantLoop Minimum Temperature=1.0 {C}
> > ** ~~~ ** PlantLoop Maximum Temperature=98.0 {C}
> > ** ~~~ ** PlantLoop Flow Request (SupplySide)=0.0 {kg/s}
> > ** ~~~ ** PlantLoop Flow Request (DemandSide)=0.1 {kg/s}
> > ** ~~~ ** PlantLoop Node (SupplySide) "CHW LOOP SUPPLY SIDE OUTLET" has mass flow rate =0.1 {kg/s}
> > ** ~~~ ** PlantLoop PumpHeat (SupplySide)=3.4 {W}
> > ** ~~~ ** PlantLoop PumpHeat (DemandSide)=0.0 {W}
> > ** ~~~ ** PlantLoop Cooling Demand=218.9 {W}
> > ** ~~~ ** PlantLoop Heating Demand=0.0 {W}
> > ** ~~~ ** PlantLoop Demand not Dispatched=0.0 {W}
> > ** ~~~ ** PlantLoop Unmet Demand=62323.8 {W}
> > ** ~~~ ** PlantLoop Capacity=120000.0 {W}
> > ** ~~~ ** PlantLoop Capacity (SupplySide)=120000.0 {W}
> > ** ~~~ ** PlantLoop Capacity (DemandSide)=0.0 {W}
> > ** ~~~ ** PlantLoop Operation Scheme=CHW LOOP OPERAZIONE
> > ** ~~~ ** PlantLoop Operation Dispatched Load = 218.9 {W}
> > ** ~~~ ** PlantLoop Operation Dispatched Load (SupplySide)= 218.9 {W}
> > ** ~~~ ** PlantLoop Operation Dispatched Load (DemandSide)= 0.0 {W}
> > ** ~~~ ** Branches on the Loop.
> >
> >
> > I've tried to check the GSHPSimple-GLHE in the ExampleFile and get some changes but it doesn't work... Any ideas????
> > Maria
> >
>

--
Edwin Lee, PhD
Engineer, Commercial Buildings Research Staff

National Renewable Energy Laboratory

Edwin Lee, PhD

Engineer, Commercial Buildings Research Staff

National Renewable Energy Laboratory