modelSolarCollector_L1_constProp
Extends from TransiEnt.Basics.Icons.SolarThermalCollector.
Information
1. Purpose of model
A simple solar collector providing useful energy gain as recommended by EN 12975 steady state thermal performance equation [1]. Effective heat capacity was added for transient behavior according to [2].
2. Level of detail, physical effects considered, and physical insight
No physical but parameter based model. Model considers heat loss to ambience but no convection, and pressure losses (linear or quadratic).
No TILMedia models used because they produce warnings at temperatures below 0°C even if no heat flow is generated.
3. Limits of validity
Without effective heat capacity only valid for steady state performance.
Model ignores wind speed.
4. Interfaces
waterIn: water inlet
waterOut: water outlet
T_in: output of temperature at inlet
T_out: output of temperature at outlet
G: output of total irradiance
irradiance_direct_measured_input: input of direct irradiance
irradiance_diffuse_horizontal_input: input of diffuse horizontal irradiance
5. Nomenclature
(no remarks)
6. Governing Equations
7. Remarks for Usage
This solar collector can be used for temperatures below 0°C as well.
8. Validation
not validated yet but tested in the check model "TransiEnt.Producer.Heat.SolarThermal.Check.TestCollectorFluidCycle_constProp"
9. References
[1] P. Kovacs, “Quality Assurance in solar thermal heating and cooling technology – keeping track with recent and upcoming developments. A guide to the standard EN 12975,” Brussels, 2012.
[2] T. Osório and M. J. Carvalho, “Testing of solar thermal collectors under transient conditions,” Sol. Energy, vol. 104, pp. 71–81, 2014.
10. Version History
Model created by Tobias Toerber (tobias.toerber@tuhh.de), Jul 2015
Model modified by Sascha Guddusch (sascha.guddusch@tuhh.de), May 2016
Model modified by Anne Senkel (anne.senkel@tuhh.de), Mar 2017
Model modified by Lisa Andresen (andresen@tuhh.de), Apr. 2017
Model modified by Oliver Schülting (oliver.schuelting@tuhh.de), May 2018: added possibility to use inputs for solar irradiation
Model modified by Oliver Schülting (oliver.schuelting@tuhh.de), Aug 2018: added boolean 'UseStationaryCalculationMethod' to deactive instationary part of heat flow calculation '-c_eff*der_T'. Results are nearly the same but unrealistic peaks can be avoided if calculation is stationary
Model modified by Carsten Bode (c.bode@tuhh.de), Nov 2018: replaced fluid objects by equations, eliminated m_flowInv and x
Model modified by Anne Hagemeier (anne.hagemeier@umsicht.fraunhofer.de), Aug 2021: enabled the model to be useable without fluid ports
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| SI.Density | d | 985.269 | Density of medium |
| SI.SpecificHeatCapacity | c | 4190.96 | Specific heat capacity of medium |
| SI.SpecificEnthalpy | h_0 | 59.6504 | Specific enthalpy of medium at 0°C |
| General | |||
| TILMedia.VLEFluidTypes.BaseVLEFluid | medium | simCenter.fluid1 | |
| Boolean | useHomotopy | simCenter.useHomotopy | true = homotopy method is used during initialisation |
| General › General | |||
| SI.HeatFlowRate | Q_flow_n | Nominal heat flow rate (for cost calculation) | |
| SI.Area | area | Aperture area | |
| Real | c_eff | Effective thermal capacity of the collector | |
| SI.Irradiance | G_min | 0 | Minimum Irradiance before collector is working |
| Boolean | UseStationaryCalculationMethod | true | Choose if calculation uses only stationary equations or not |
| Boolean | useFluidPorts | true | True if fluid ports shall be used |
| Coefficients for thermal performance | |||
| Real | eta_0 | Zero-loss collector efficiency | |
| Real | a1 | Heat loss coefficient at (T_m - T_amb) = 0 | |
| Real | a2 | Temperature dependent heat loss coefficient | |
| Pressure drop | |||
| Boolean | noFriction | true | true = assume no pressure loss due to friction |
| Integer | n_serial | 1 | Number of collectors in series (max. 12) |
| Real | a | 0 | Linear pressure drop coefficient |
| Real | b | 0 | Quadratic pressure drop coefficient |
| SI.Height | z1 | 0 | Height inlet |
| SI.Height | z2 | 0 | Height outlet |
| Irradiance › Losses | |||
| Real | Soiling | 0 | Average annual losses of radiation in % due to soiling |
| Irradiance › Solartime | |||
| SI.Angle | longitude_local | Modelica.Units.Conversions.from_deg(10) | longitude of the local position, east positive, 10 East for Hamburg |
| SI.Angle | longitude_standard | Modelica.Units.Conversions.from_deg(15) | needed for calculation of coordinated universal time (utc), 15 for central european time, 30 for central european summer time |
| Irradiance › Extraterrestrial Irradiance | |||
| SI.Angle | latitude | Modelica.Units.Conversions.from_deg(53.55) | latitude of the local position, north posiive, 53,55 North for Hamburg |
| SI.Angle | slope | Modelica.Units.Conversions.from_deg(53.55) | slope of the tilted surface, assumption |
| SI.Angle | surfaceAzimuthAngle | 0 | surface azimuth angle |
| Irradiance › Skymodel | |||
| Real | reflectance_ground | 0.2 | reflectance of the ground |
| Boolean | direct_normal | true | Is the direct irradiance measured on a surface normal to irradiance? |
| Boolean | use_input_data | false | choose if input data is given by inputs - if not, simCenter data is used |
| IAM › General | |||
| Integer | kind | 1 | IAM for direct Irradiance |
| Real | constant_iam_dir | 1 | constant IAM for direct irradiation |
| Real | constant_iam_diff | 1 | constant IAM for diffuse irradiation |
| Real | constant_iam_ground | 1 | constant IAM for ground-reflected irradiation |
| Real | b0 | 1 | assumption: constant b0-value for IAM=1-b0*(1/cos(theta)-1) |
| Real | iam_SRCC | {1, 1, 1, 1, 1, 1, 1, 1} | IAM for theta = 0, 10, 20, ..., 70 |
| Modelica.Units.NonSI.Angle_deg | theta | {0, 10, 20, 30, 40, 50, 60, 70} | |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| TransiEnt.Basics.Interfaces.Thermal.FluidPortOut | waterPortOut | ||
| TransiEnt.Basics.Interfaces.Thermal.FluidPortIn | waterPortIn | ||
| Basics.Interfaces.General.TemperatureOut | T_in_int | ||
| TransiEnt.Basics.Interfaces.General.TemperatureOut | T_out | ||
| Modelica.Blocks.Interfaces.RealOutput | G | G_total | |
| Modelica.Blocks.Interfaces.RealOutput | Q_flow_out | ||
| Modelica.Blocks.Interfaces.RealOutput | m_flow_int | ||
| TransiEnt.Basics.Interfaces.Ambient.IrradianceIn | irradiance_direct_measured_input | ||
| TransiEnt.Basics.Interfaces.Ambient.IrradianceIn | irradiance_diffuse_horizontal_input | ||
| Modelica.Blocks.Interfaces.RealInput | m_flow | ||
| Basics.Interfaces.General.TemperatureIn | T_inflow | ||
| Basics.Interfaces.General.TemperatureOut | T_in |
Components
Contents
| Name | Description |
|---|---|
 Skymodel | choose between HDKR and isotropic sky model |
 CostRecordSolarThermal |