Buildings.Fluid.SolarCollectors
Package with models for solar collectors
Information
This package contains models which can be used to simulate solar thermal systems and examples describing their use.Extends from Modelica.Icons.Package (Icon for standard packages).
Package Content
| Name | Description |
|---|---|
 UsersGuide
|
User's Guide |
 ASHRAE93
|
Model of a solar thermal collector according to the ASHRAE Standard 93 |
| EN12975
|
Model of a solar thermal collector according to the ASHRAE Standard 93 |
 Controls
|
Package for solar thermal collector controllers |
 Data
|
Data for solar thermal collectors |
 Types
|
Package with type definitions used in solar collector data records |
 Examples
|
Examples demonstrating the use of models in the SolarCollectors package |
| Validation
|
Collection of validation models |
 BaseClasses
|
Package with base classes for Buildings.Fluid.SolarCollectors |
Buildings.Fluid.SolarCollectors.ASHRAE93
Model of a solar thermal collector according to the ASHRAE Standard 93
Information
This component models a solar thermal collector according to the ASHRAE93 test standard.
References
ASHRAE 93-2010 -- Methods of Testing to Determine the Thermal Performance of Solar Collectors (ANSI approved).
EnergyPlus 23.2.0 Engineering Reference.
Extends from Buildings.Fluid.SolarCollectors.BaseClasses.PartialSolarCollector (Partial model for solar collectors).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Integer | nSeg | 3 | Number of segments used to discretize the collector model |
| Angle | azi | Surface azimuth (0 for south-facing; -90 degree for east-facing; +90 degree for west facing [rad] | |
| Angle | til | Surface tilt (0 for horizontally mounted collector) [rad] | |
| Real | rho | Ground reflectance [1] | |
| HeatCapacity | CTot | if per.CTyp == Buildings.Flu... | Heat capacity of solar collector with fluid [J/K] |
| Shading | |||
| Boolean | use_shaCoe_in | false | Enables an input connector for shaCoe |
| Real | shaCoe | 0 | Shading coefficient. 0.0: no shading, 1.0: full shading |
| Area declarations | |||
| NumberSelection | nColType | Buildings.Fluid.SolarCollect... | Selection of area specification format |
| Integer | nPanels | 0 | Desired number of panels in the simulation |
| Area | totalArea | 0 | Total area of panels in the simulation [m2] |
| Configuration declarations | |||
| SystemConfiguration | sysConfig | Buildings.Fluid.SolarCollect... | Selection of system configuration |
| Integer | nPanelsPar | 0 | Number of array panels in parallel |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Real | mSenFac | 1 | Factor for scaling the sensible thermal mass of the volume |
| Advanced | |||
| Dynamics | |||
| Dynamics | massDynamics | energyDynamics | Type of mass balance: dynamic (3 initialization options) or steady state, must be steady state if energyDynamics is steady state |
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
| Initialization | |||
| AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
| Temperature | T_start | Medium.T_default | Start value of temperature [K] |
| MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
| ExtraProperty | C_nominal[Medium.nC] | fill(1E-2, Medium.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Flow resistance | |||
| Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistance | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaM | 0.1 | Fraction of nominal flow rate where flow transitions to laminar |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| input RealInput | shaCoe_in | Shading coefficient |
| Bus | weaBus | Weather data bus |
Modelica definition
model ASHRAE93 "Model of a solar thermal collector according to the ASHRAE Standard 93"
extends Buildings.Fluid.SolarCollectors.BaseClasses.PartialSolarCollector(
redeclare Buildings.Fluid.SolarCollectors.Data.GenericASHRAE93 per);
BaseClasses.ASHRAESolarGain solGai(
redeclare package Medium = Medium,
final nSeg=nSeg,
final til=til,
final incAngDat=per.incAngDat,
final incAngModDat=per.incAngModDat,
final y_intercept=per.y_intercept,
final use_shaCoe_in=use_shaCoe_in,
final shaCoe=shaCoe,
final A_c=ATot_internal)
"Identifies heat gained from the sun using the ASHRAE Standard 93 calculations";
BaseClasses.ASHRAEHeatLoss heaLos(
redeclare package Medium = Medium,
final nSeg=nSeg,
final slope=per.slope,
final A_c=ATot_internal)
"Calculates the heat lost to the surroundings using the ASHRAE Standard 93 calculations";
equation
// Make sure the model is only used with the ASHRAE ratings data, and slope < 0
assert(per.slope < 0,
"In " + getInstanceName() + ": The heat loss coefficient from the ASHRAE ratings data must be strictly negative. Obtained slope = " + String(per.slope));
connect(weaBus.TDryBul, heaLos.TEnv);
connect(HDirTil.inc, solGai.incAng);
connect(HDirTil.H, solGai.HDirTil);
connect(HDifTilIso.HGroDifTil, solGai.HGroDifTil);
connect(HDifTilIso.HSkyDifTil, solGai.HSkyDifTil);
connect(shaCoe_in, solGai.shaCoe_in);
connect(solGai.QSol_flow, QGai.Q_flow);
connect(temSen.T, heaLos.TFlu);
connect(temSen.T, solGai.TFlu);
connect(heaLos.QLos_flow, QLos.Q_flow);
end ASHRAE93;
Buildings.Fluid.SolarCollectors.EN12975
Model of a solar thermal collector according to the ASHRAE Standard 93
Information
This component models a solar thermal collector according to the EN12975 test standard.
References
CEN 2022, European Standard 12975:2022, European Committee for Standardization
EnergyPlus 23.2.0 Engineering Reference
Extends from Buildings.Fluid.SolarCollectors.BaseClasses.PartialSolarCollector (Partial model for solar collectors).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Integer | nSeg | 3 | Number of segments used to discretize the collector model |
| Angle | azi | Surface azimuth (0 for south-facing; -90 degree for east-facing; +90 degree for west facing [rad] | |
| Angle | til | Surface tilt (0 for horizontally mounted collector) [rad] | |
| Real | rho | Ground reflectance [1] | |
| HeatCapacity | CTot | if per.CTyp == Buildings.Flu... | Heat capacity of solar collector with fluid [J/K] |
| Shading | |||
| Boolean | use_shaCoe_in | false | Enables an input connector for shaCoe |
| Real | shaCoe | 0 | Shading coefficient. 0.0: no shading, 1.0: full shading |
| Area declarations | |||
| NumberSelection | nColType | Buildings.Fluid.SolarCollect... | Selection of area specification format |
| Integer | nPanels | 0 | Desired number of panels in the simulation |
| Area | totalArea | 0 | Total area of panels in the simulation [m2] |
| Configuration declarations | |||
| SystemConfiguration | sysConfig | Buildings.Fluid.SolarCollect... | Selection of system configuration |
| Integer | nPanelsPar | 0 | Number of array panels in parallel |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Real | mSenFac | 1 | Factor for scaling the sensible thermal mass of the volume |
| Advanced | |||
| Dynamics | |||
| Dynamics | massDynamics | energyDynamics | Type of mass balance: dynamic (3 initialization options) or steady state, must be steady state if energyDynamics is steady state |
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
| Initialization | |||
| AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
| Temperature | T_start | Medium.T_default | Start value of temperature [K] |
| MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
| ExtraProperty | C_nominal[Medium.nC] | fill(1E-2, Medium.nC) | Nominal value of trace substances. (Set to typical order of magnitude.) |
| Flow resistance | |||
| Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistance | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaM | 0.1 | Fraction of nominal flow rate where flow transitions to laminar |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| input RealInput | shaCoe_in | Shading coefficient |
| Bus | weaBus | Weather data bus |
Modelica definition
model EN12975 "Model of a solar thermal collector according to the ASHRAE Standard 93"
extends Buildings.Fluid.SolarCollectors.BaseClasses.PartialSolarCollector(
redeclare Buildings.Fluid.SolarCollectors.Data.GenericEN12975 per);
Buildings.Fluid.SolarCollectors.BaseClasses.EN12975SolarGain solGai(
redeclare package Medium = Medium,
final nSeg=nSeg,
final incAngDat=per.incAngDat,
final incAngModDat=per.incAngModDat,
final iamDiff=per.IAMDiff,
final eta0=per.eta0,
final use_shaCoe_in=use_shaCoe_in,
final shaCoe=shaCoe,
final A_c=ATot_internal)
"Identifies heat gained from the sun using the EN12975 standard calculations";
Buildings.Fluid.SolarCollectors.BaseClasses.EN12975HeatLoss heaLos(
redeclare package Medium = Medium,
final nSeg=nSeg,
final a1=per.a1,
final a2=per.a2,
final A_c=ATot_internal)
"Calculates the heat lost to the surroundings using the EN12975 standard calculations";
equation
// Make sure the model is only used with the EN ratings data, and hence a1 > 0
assert(per.a1 > 0,
"In " + getInstanceName() + ": The heat loss coefficient from the EN 12975 ratings data must be strictly positive. Obtained a1 = " + String(per.a1));
connect(shaCoe_internal, solGai.shaCoe_in);
connect(weaBus.TDryBul, heaLos.TEnv);
connect(HDirTil.inc, solGai.incAng);
connect(HDifTilIso.H, solGai.HSkyDifTil);
connect(HDirTil.H, solGai.HDirTil);
connect(shaCoe_in, solGai.shaCoe_in);
connect(heaLos.TFlu, temSen.T);
connect(heaLos.QLos_flow, QLos.Q_flow);
connect(solGai.QSol_flow, QGai.Q_flow);
connect(temSen.T, solGai.TFlu);
end EN12975;