Hi everybody, I am modeling a NZEB building equipped with a ground source heat pump that feeds the water circuit dedicated to heating and cooling with 2 tubes fancoils. The HP is used to produce hot water from October to April, it is switched off untill June, then it is used to produce chilled water from June untill September, it is switched off again untill October.
In openstudio, I have modeled this using :
-Heat Pump - Water To Water - Cooling (Os:HeatPump:WaterToWater:EquationFit:Cooling)
-Heat Pump - Water To Water - Heating (Os:HeatPump:WaterToWater:EquationFit:Heating)
which are then connected, respectively, to a Fan Coil with Cycling Fan - Cooling Coil (Os:Coil:Cooling:Water) and a Fan Coil with Cycling Fan - Heating Coil Os:Coil:Heating:Water.
I have correctly modeled the plant loops, but I cannot find a way to implement the control logic descripted above. In the current model, the two heat pumps object are working at the same time, providing cooling and heating also during winter and summer, as well as functioning during the period of time in which the HP should be switched off. Although, this was acceptable on a first approach, it is not currently depicting the real plant scheme.
The main issue is that the real HP is not able to deliver both chilled and hot water, the operating mode is manually switched between the two configuration at the beginning of each season. On the other hand, this is linked to the fact that fancoils are only modeled, in Openstudio, as 4 tubes which is not the case for the real fancoils.
I decided to give an availability schedule to the fancoil heat exchanger, shutting them down in the appropriate time-window. However this induced the following error:
** Severe ** Plant temperatures are getting far too hot, check controls and relative loads and capacities
* ~~~ * Environment=RUN PERIOD 1, at Simulation time=04/28 05:45 - 05:50
* ~~~ * PlantLoop Name (DemandSide)= ACQUA CALDA FANCOIL
* ~~~ * PlantLoop Setpoint Temperature=55.0 {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 (DemandSide) "NODE 48" has temperature=300.0 {C}
* ~~~ * PlantLoop Inlet Node (DemandSide) "NODE 47" has temperature=300.0 {C}
* ~~~ * PlantLoop Minimum Temperature=0.0 {C}
* ~~~ * PlantLoop Maximum Temperature=100.0 {C}
* ~~~ * PlantLoop Flow Request (SupplySide)=0.0 {kg/s}
* ~~~ * PlantLoop Flow Request (DemandSide)=1.3 {kg/s}
.....the error message continues*
I have added bypass branches to fancoil heat exchangers in their respective water loops, changed the fancoil loops pumps to variable volume ones with intermittent control (as I have read here, and the linked asnwers there) but with no avail. Others answer in the forum simply did not adress my problem, or I have just being searching in the wrong places.
My question is, is there a way to solve this issue in a smarter way?
