Buildings.Templates.Plants.HeatPumps.Validation
Package with validation models
Information
This package contains models validating the templates within Buildings.Templates.Plants.HeatPumps for various system configurations.
The models also illustrate parameter propagation from the top-level
HVAC system record datAll.
Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).
Package Content
| Name | Description |
|---|---|
 AirToWaterPolyvalent
|
Validation of AWHP plant template with polyvalent (4-pipe) units only |
| AirToWaterReversibleHeatRecovery
|
Validation of AWHP plant template with reversible heat pumps and heat recovery chiller |
| AirToWaterReversiblePolyvalent
|
Validation of AWHP plant template with reversible (2-pipe) and polyvalent (4-pipe) units |
 UserProject
|
Package with configured models |
Buildings.Templates.Plants.HeatPumps.Validation.AirToWaterPolyvalent
Validation of AWHP plant template with polyvalent (4-pipe) units only
Information
This model extends Buildings.Templates.Plants.HeatPumps.Validation.AirToWaterReversibleHeatRecovery and validates the AWHP plant template Buildings.Templates.Plants.HeatPumps.AirToWater in a configuration with three polyvalent (4-pipe) heat pumps with lead/lag alternation, and a primary-only distribution system with headered pumps.
The modeling assumptions are reproduced from the parent validation model, except for the load profile, which is deliberately chosen to increase simultaneous heating and cooling loads, exercising the mode selection and staging logic for polyvalent heat pumps.
Simulating this model shows how the plant responds to a varying load by
- enabling and alternating the polyvalent units in different operating modes,
- resetting the supply temperature and remote differential pressure in both the CHW and HW loops based on the valve position,
- staging and controlling the primary headered pumps to meet the remote differential pressure setpoint.
Extends from Buildings.Templates.Plants.HeatPumps.Validation.AirToWaterReversiblePolyvalent (Validation of AWHP plant template with reversible (2-pipe) and polyvalent (4-pipe) units).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | Water | Main medium (common for CHW and HW) | |
| PressureDifference | dpTer_nominal | 3E4 | Liquid pressure drop across terminal unit at design conditions [Pa] |
| PressureDifference | dpValve_nominal | dpTer_nominal | Terminal unit control valve pressure drop at design conditions [Pa] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Connectors
| Type | Name | Description |
|---|---|---|
| Bus | busAirHan | AHU control bus |
| Bus | busPla | Plant control bus |
Modelica definition
Buildings.Templates.Plants.HeatPumps.Validation.AirToWaterReversibleHeatRecovery
Validation of AWHP plant template with reversible heat pumps and heat recovery chiller
Information
This model validates Buildings.Templates.Plants.HeatPumps.AirToWater by simulating a 24-hour period with overlapping heating and cooling loads. The heating loads reach their peak value first, the cooling loads reach it last.
Three equally sized, lead/lag alternated heat pumps are modeled. A heat
recovery chiller (HRC) is included
(pla.typ=Buildings.Templates.Plants.Controls.Types.PlantHeatPump.ReversibleHeatRecovery)
and connected to the HW and CHW return pipes (sidestream integration). A
unique aggregated load is modeled on each loop using a heat exchanger
component exposed to conditioned space air, and a two-way modulating valve.
An importance multiplier of 10 is applied to the plant requests and
reset requests generated from the valve position.
The user can modify the plant parameter pla.typ to switch
between a cooling and heating system (the default setting) and a
heating-only system. Advanced equipment and control options can be modified
via the parameter dialog of the plant component.
Simulating this model shows how the plant responds to a varying load by
- staging or unstaging the AWHPs and the HRC with the associated primary pumps,
- rotating lead/lag alternate equipment to ensure even wear,
- resetting the supply temperature and remote differential pressure in both the CHW and HW loops based on the valve position,
- staging and controlling the secondary pumps to meet the remote differential pressure setpoint.
Note that the HRC model does not explicitly represent compressor cycling. As a result, the cycling-based disabling condition specified in Buildings.Templates.Plants.Controls.HeatRecoveryChillers.Enable is never triggered. This limitation may lead to overestimating the HRC operating time.
Details
By default, all valves within the plant are modeled considering a linear
variation of the pressure drop with the flow rate
(pla.linearized=true), as opposed to the quadratic relationship
usually considered for a turbulent flow regime. By limiting the size of the
system of nonlinear equations, this setting reduces the risk of solver
failure and the time to solution for testing various plant configurations.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | Buildings.Media.Water | Main medium (common for CHW and HW) | |
| AirToWaterReversibleHeatRecovery | datAll | datAll(pla(final cfg=pla.cfg)) | Plant parameters |
| PressureDifference | dpTer_nominal | 3E4 | Liquid pressure drop across terminal unit at design conditions [Pa] |
| PressureDifference | dpValve_nominal | dpTer_nominal | Terminal unit control valve pressure drop at design conditions [Pa] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Main medium (common for CHW and HW) | |
| Bus | busAirHan | AHU control bus |
| Bus | busPla | Plant control bus |
Modelica definition
Buildings.Templates.Plants.HeatPumps.Validation.AirToWaterReversiblePolyvalent
Validation of AWHP plant template with reversible (2-pipe) and polyvalent (4-pipe) units
Information
This model extends Buildings.Templates.Plants.HeatPumps.Validation.AirToWaterReversibleHeatRecovery and validates the AWHP plant template Buildings.Templates.Plants.HeatPumps.AirToWater in a configuration with two reversible (2-pipe) heat pumps with lead/lag alternation and one polyvalent (4-pipe) heat pump.
The modeling assumptions are reproduced from the parent validation model, except for the load profile, which is deliberately chosen to increase simultaneous heating and cooling loads, exercising the mode selection and staging logic for polyvalent heat pumps.
Simulating this model shows how the plant responds to a varying load by
- staging the polyvalent unit up first in simultaneous heating and cooling mode,
- enabling and alternating the reversible units in heating or cooling mode,
- switching the polyvalent unit to cooling-only mode when the heating load falls to zero,
- enabling the dedicated primary pumps as required by the served equipment,
- resetting the supply temperature and remote differential pressure in both the CHW and HW loops based on the valve position,
- staging and controlling the secondary pumps to meet the remote differential pressure setpoint.
Extends from Buildings.Templates.Plants.HeatPumps.Validation.AirToWaterReversibleHeatRecovery (Validation of AWHP plant template with reversible heat pumps and heat recovery chiller).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | Water | Main medium (common for CHW and HW) | |
| PressureDifference | dpTer_nominal | 3E4 | Liquid pressure drop across terminal unit at design conditions [Pa] |
| PressureDifference | dpValve_nominal | dpTer_nominal | Terminal unit control valve pressure drop at design conditions [Pa] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Connectors
| Type | Name | Description |
|---|---|---|
| Bus | busAirHan | AHU control bus |
| Bus | busPla | Plant control bus |