modelIndirect
Indirect cooling energy transfer station for district energy systems
Extends from Buildings.DHC.ETS.BaseClasses.PartialIndirect (Partial indirect energy transfer station for district energy systems).
Information
Indirect cooling energy transfer station (ETS) model that controls the building chilled water supply temperature by modulating a primary control valve on the district supply side. The design is based on a typical district cooling ETS described in ASHRAE's District Cooling Guide. As shown in the figure below, the building pumping design (constant/variable) is specified on the building side and not within the ETS.
Reference
American Society of Heating, Refrigeration and Air-Conditioning Engineers. (2019). Chapter 5: End User Interface. In District Cooling Guide, Second Edition and Owner's Guide for Buildings Served by District Cooling.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Buildings.Fluid.Data.Fuels.Generic[nFue] | fue (from PartialETS) | Fuel type | |
| Configuration | |||
| TypDisSys | typ (from PartialETS) | Buildings.DHC.Types.DistrictSystemType.CombinedGeneration2to4 | Type of district system |
| Integer | nPorts_aHeaWat (from PartialETS) | 0 | Number of heating water return ports |
| Integer | nPorts_bHeaWat (from PartialETS) | 0 | Number of heating water supply ports |
| Integer | nPorts_aChiWat (from PartialETS) | 0 | Number of chilled water return ports |
| Integer | nPorts_bChiWat (from PartialETS) | 0 | Number of chilled water supply ports |
| Boolean | have_heaWat (from PartialETS) | false | Set to true if the ETS supplies heating water |
| Boolean | have_hotWat (from PartialETS) | false | Set to true if the ETS supplies hot water |
| Boolean | have_chiWat (from PartialETS) | false | Set to true if the ETS supplies chilled water |
| Boolean | have_fan (from PartialETS) | false | Set to true if fan power is computed |
| Boolean | have_pum (from PartialETS) | false | Set to true if pump power is computed |
| Boolean | have_eleHea (from PartialETS) | false | Set to true if the ETS has electric heating system |
| Integer | nFue (from PartialETS) | 0 | Number of fuel types (0 means no combustion system) |
| Boolean | have_eleCoo (from PartialETS) | false | Set to true if the ETS has electric cooling system |
| Boolean | have_weaBus (from PartialETS) | false | Set to true to use a weather bus |
| Assumptions | |||
| Boolean | allowFlowReversalSer (from PartialETS) | false | Set to true to allow flow reversal on service side |
| Boolean | allowFlowReversalBui (from PartialETS) | false | Set to true to allow flow reversal on building side |
| Nominal condition | |||
| Modelica.Units.SI.HeatFlowRate | QHeaWat_flow_nominal (from PartialETS) | 0 | Nominal capacity of heating system (>=0) |
| Modelica.Units.SI.HeatFlowRate | QHotWat_flow_nominal (from PartialETS) | 0 | Nominal capacity of hot water production system (>=0) |
| Modelica.Units.SI.HeatFlowRate | QChiWat_flow_nominal (from PartialETS) | 0 | Nominal capacity of cooling system (<=0) |
| Modelica.Units.SI.MassFlowRate | mDis_flow_nominal (from PartialIndirect) | Nominal mass flow rate of district side | |
| Modelica.Units.SI.MassFlowRate | mBui_flow_nominal (from PartialIndirect) | Nominal mass flow rate of building side | |
| Modelica.Units.SI.PressureDifference | dpConVal_nominal (from PartialIndirect) | 6000 | Nominal pressure drop of fully open control valve |
| Heat exchanger | |||
| Modelica.Units.SI.PressureDifference | dp1_nominal (from PartialIndirect) | Nominal pressure difference on primary side | |
| Modelica.Units.SI.PressureDifference | dp2_nominal (from PartialIndirect) | Nominal pressure difference on secondary side | |
| Boolean | use_Q_flow_nominal (from PartialIndirect) | true | Set to true to specify Q_flow_nominal and temeratures, or to false to specify effectiveness |
| Modelica.Units.SI.HeatFlowRate | Q_flow_nominal (from PartialIndirect) | Nominal heat transfer (positive for heat transfer from district to building) | |
| Modelica.Units.SI.Temperature | T_a1_nominal (from PartialIndirect) | Nominal temperature at port a1 (district supply) | |
| Modelica.Units.SI.Temperature | T_a2_nominal (from PartialIndirect) | Nominal temperature at port a2 (building return) | |
| Modelica.Units.SI.Efficiency | eta (from PartialIndirect) | 0.8 | Constant effectiveness |
| PID controller | |||
| Modelica.Blocks.Types.SimpleController | controllerType (from PartialIndirect) | Modelica.Blocks.Types.SimpleController.PI | Type of controller |
| Real | k (from PartialIndirect) | 1 | Gain of controller |
| Modelica.Units.SI.Time | Ti (from PartialIndirect) | 120 | Time constant of integrator block |
| Modelica.Units.SI.Time | Td (from PartialIndirect) | 0.1 | Time constant of derivative block |
| Real | yMax (from PartialIndirect) | 1 | Upper limit of output |
| Real | yMin (from PartialIndirect) | 0.01 | Lower limit of output |
Connectors
Components
Revisions
-
March 27, 2024, by David Blum:
Update icon and fix port orientation to align with convention.
This is for issue #3606. -
May 30, 2023, by David Blum:
Change to extend fromBuildings.DHC.ETS.BaseClasses.PartialDirect. -
March 16, 2023, by David Blum:
Fixed building supply temperature controller parameterreverseActingby changing fromtruetofalse.
This is for issue 3299. -
January 11, 2023, by Michael Wetter:
Changed controls to use CDL. Changed PID to PI as default for controller. -
March 21, 2022, by Chengnan Shi:
Update with base class partial model. - Novermber 13, 2019, by Kathryn Hinkelman:
First implementation.