Structure of a ddck-file¶
The file sctructure of the ddck files is shown in the example.ddck file in the pytrnsys_ddck repository root. Each ddck should contain the following parts. Some parts can be empty if not used.
Header¶
In the header the name of the ddck as well as a contact persion, the creation date and some information about the last changes are specified. In addition, there is a section for general descriptions about the ddck:
*******************************
**BEGIN example.ddck
*******************************
*****************************************
** Contact person : author
** Creation date : date
** Last changes : date, name
*****************************************
***************************************************************************
** Description:
** Overall description of the ddck file
** TODO: Any improvements needed
***************************************************************************
Inputs from hydraulic solver¶
The pytrnsys ddcks are designed to be used in combination with the hydraulic solver type 935. In each timestep the hydraulic solver computes all mass flows and component input temperatures starting depending on the component output temperatures, the pump powers and the valve positions. Therefore, the mass flows and component input temperatures are outputs of the hydraulic solver that have to be connected to the component ddcks as inputs:
***********************************
** inputs from hydraulic solver
***********************************
** tIn from hydraulic
** tIn from hydraulic with placeholder:
** tIn = @temp(PortName, DefaultPipeName)
** mIn from hydraulic
** mIn from hydraulic with placeholder:
** mIn = @mfr(PortName, DefaultPipeName)
Outputs to the hydraulic solver¶
Similar to the inputs, the output temperatures of the component should be stated here, such that they are easily accessible to be connected to the hydraulics file:
***********************************
** outputs to hydraulic solver
***********************************
** which outputs will be used to connect the hydraulic solver
** typically tOutType will be defined here to be used in the hydraulic ddck
** tOutType with placeholder:
** @temp(PortName, DefaultName) = tOut
Outputs to the energy balance¶
In the processing, pytrnsys automatically computes the systems heat and electricity energy balance. All variables that should be collected for the energy balance have to be specified in this section according to the right nomenclature:
******************************************************************************************
** outputs to energy balance in kWh and ABSOLUTE value
** Following this naming standard : qSysIn_name, qSysOut_name, elSysIn_name, elSysOut_name
******************************************************************************************
** Add here those variables that will go into the overall energy balance of the system
** These values will be used to automatically generate the energy balance
Dependencies with other ddck files¶
In order to enhance modularization, dependencies with other ddcks should be kept minimal. Dependencies that cannot be avoided and are neither part of the component-database relation or the general variables should be declarated and reassigned to an internally used variable in this part:
***********************************
** Dependencies with other ddck
***********************************
** Re-assing here the variables necessary from other types
** variableInternal = variableExternal
** Exception: those from general variables
Outputs to other ddck files¶
Variables that are designated to be used in other ddck files should be added here:
***********************************
** outputs to other ddck
***********************************
** Add here the outputs of the TYPE or TYPES that will be used in other types
** Exception: those for printers and so on dont need to be here.
Type section¶
TRNSYS has its own syntax that calls the type dll files. This core part of the ddck goes here:
***********************************
** Begin TYPE
***********************************
Component printers¶
Each component should have a monthly as well as an hourly printer. This helps to simplify the setup and the processing of the simulation. In addition, an online plotter is a nice tool for the debugging of the system:
***********************************
** Monthly printer
***********************************
***********************************
** Hourly printer
***********************************
***********************************
** Online plotter
***********************************
Hydraulics files¶
The hydraulics file represents the systems hydraulics layout. Each pytrnsys example system except the pv battery system has its own hydraulic layout file. In order to create your own hydraulic files that represent the hydraulics of your choice you need access to the pytrnsys GUI. The hydraulics file are not part of the ddck repository. The hydraulic files of the example systems are located in the example system folder of pytrnsys_examples.
Examples¶
The following example shows the ddck file of the solar collector type 1 used in the solar domestic hot water system:
*******************************
**BEGIN Type1.ddck
*******************************
*****************************************
** Contact person : Dani Carbonell
** Creation date : 10.01.2010
** Last changes : 03.2020 Jeremias Schmidli
*****************************************
***************************************************************************
** Description:
** Collector model using efficiency curve efficiency
***************************************************************************
***********************************
** inputs from hydraulic solver
***********************************
EQUATIONS 2
TCollIn = TPiColIn
MfrColl = ABS(MfrPiColIn)
***********************************
** outputs to hydraulic solver
***********************************
EQUATIONS 1
TCollOut = [28,1]
***********************************
** outputs to other ddck
***********************************
******************************************************************************************
** outputs to energy balance in kWh and ABSOLUTE value
** Following this naming standard : qSysIn_name, qSysOut_name, elSysIn_name, elSysOut_name
******************************************************************************************
EQUATIONS 1
qSysIn_Collector = PColl_kW
***********************************
** Dependencies with other ddck
***********************************
EQUATIONS 1
pumpColOn = puColOn
CONSTANTS 2
C_tilt = slopeSurfUser_1 ! @dependencyDdck Collector tilt angle / slope [°]
C_azim = aziSurfUSer_1 ! @dependencyDdck Collector azimuth (0:s, 90:w, 270: e) [°]
EQUATIONS 4
**surface-8
IT_Coll_kJhm2 = IT_surfUser_1 ! Incident total radiation on collector plane, kJ/hm2
IB_Coll_kJhm2 = IB_surfUser_1 ! incident beam radiation on collector plane, kJ/hm2
ID_Coll_kJhm2 = ID_surfUser_1 ! diffuse and ground reflected irradiance on collector tilt
AI_Coll = AI_surfUser_1 ! incident angle on collector plane, °
EQUATIONS 5
IT_Coll_kW = IT_Coll_kJhm2/3600 ! Incident total radiation on collector plane, kW/m2
IB_Coll_kW = IB_Coll_kJhm2/3600 ! incident beam radiation on collector plane, kW/m2
ID_Coll_kW = ID_Coll_kJhm2/3600 ! diffuse and ground reflected irradiance on collector tilt (kW/m2)
IT_Coll_Wm2 = IT_surfUser_1/3.6
IT_Coll_kWm2 = IT_surfUser_1/3600
***********************************
** Begin CONSTANTS
***********************************
CONSTANTS 3
MfrCPriSpec = 15 ! Coll. Prim. loop spec. mass flow [kg/hm2]
AcollAp=5 ! Collector area
MfrCPriNom = MfrCPriSpec*AcollAp !
***********************************
** Begin TYPE
***********************************
UNIT 28 TYPE 1
PARAMETERS 11
nSeries ! number in series
AcollAp ! collector area
cpBri ! fluid specific heat kj(kgK
efficiencyMode ! efficiency mode
testedMfr ! tested flow rate kg/(hm2)
Eta0 ! intercept efficiency
a1 ! efficiency slope kJ/hm^2K
a2 ! efficiency curvature kJ/hm^2K^2
2 ! optical mode
FirstOrderIAM ! 1st order IAM
SecondOrderIAM ! 2nd order IAM
INPUTS 9
TCollIn
MfrColl
Tamb
IT_Coll_kJhm2
IT_H
ID_Coll_kJhm2
0,0
AI_Coll !Flo check ! JS: This was defined wrong before (C_azim, even though it is incident angle input). Now it should be correct.
C_tilt !Flo check ! JS: This should be correct
*** INITIAL INPUT VALUES
20 0 10 0 0 0 GroundReflectance 45 0
EQUATIONS 4
**MfrCout = [700,2]
Pcoll = [28,3] !kJ/h
PColl_kW = Pcoll/3600
PColl_kWm2 = PColl_kW/(AcollAp+1e-30)
PColl_Wm2 = PColl_kWm2*1000
***********************************
** Monthly printer
***********************************
CONSTANTS 1
unitPrintSol = 31
ASSIGN temp\SOLAR_MO.Prt unitPrintSol
UNIT 32 TYPE 46
PARAMETERS 6
unitPrintSol ! 1: Logical unit number, -
-1 ! 2: Logical unit for monthly summaries, -
1 ! 3: Relative or absolute start time. 0: print at time intervals relative to the simulation start time. 1: print at absolute time intervals. No effect for monthly integrations
-1 ! 4: Printing & integrating interval, h. -1 for monthly integration
1 ! 5: Number of inputs to avoid integration, -
1 ! 6: Output number to avoid integration
INPUTS 4
Time Pcoll_kW PColl_kWm2 IT_Coll_kWm2
**
Time Pcoll_kW PColl_kWm2 IT_Coll_kWm2
***********************************
** Hourly printer
***********************************
CONSTANTS 1
unitHourlyCol = 33
ASSIGN temp\SOLAR_HR.Prt unitHourlyCol
UNIT 34 TYPE 46 ! Printegrator Monthly Values for System
PARAMETERS 7
unitHourlyCol ! 1: Logical unit number, -
-1 ! 2: Logical unit for monthly summaries, -
1 ! 3: Relative or absolute start time. 0: print at time intervals relative to the simulation start time. 1: print at absolute time intervals. No effect for monthly integrations
1 ! 4: Printing & integrating interval, h. -1 for monthly integration
2 ! 5: Number of inputs to avoid integration, -
4 ! 6: Output number to avoid integration
5 ! 7: Output number to avoid integration
INPUTS 6
Pcoll_kW PColl_kWm2 IT_Coll_kWm2 TCollOut TCollIn MfrColl
**
Pcoll_kW PColl_kWm2 IT_Coll_kWm2 TCollOut TCollIn MfrColl
A specific parametrization can be added by using a ddck from the database for example the type1_CONSTANTS_cOBRAak2_8v.ddck:
******************************
**BEGIN Type1_Constants_CobraAK2_8V.ddck
*******************************
*****************************************
** Solar Thermal Data for covered collector.
** Very well performing collector Cobra AK 2.8V
** Version : v0.0
** Last Changes: Jeremias Schmidli
** Date: 10.03.2020
******************************************
CONSTANTS 11
Eta0= 0.857 ! Eta0 (a0) of collector (zero heat loss efficiency)
a1 = 4.16*3.6 ! linear heat loss coefficient of collector [kJ/hm^2K] ![W/m2K]*3.6
a2 = 0.0089*3.6 ! quadratic heat loss coefficient of collector [kJ/hm^2K^2] ![W/m2K2]*3.6
AbsorberArea = 2.435 !m2
TotArea = 2.768 !m2
nSeries = 1
efficiencyMode = 1
testedMfr = 200/AbsorberArea !l/hm2
GroundReflectance = 0.2
FirstOrderIAM = 0.108
SecondOrderIAM = 0
*******************************
**END Type1_Constants_Test.ddck
*******************************
Placeholder statements with specific syntax can be added to the inputs from hydraulic solver and Outputs to the
hydraulic solver in ddck:
*******************************
**BEGIN Type1.ddck
*******************************
*****************************************
** Contact person : Dani Carbonell
** Creation date : 10.01.2010
** Last changes : 18.05.2022
*****************************************
***************************************************************************
** Description:
** Collector model using efficiency curve efficiency
***************************************************************************
***********************************
** inputs from hydraulic solver
***********************************
EQUATIONS 2
TCollIn = @temp(In, TPiColIn)
MfrColl = ABS(@mfr(In, MfrPiColIn))
***********************************
** outputs to hydraulic solver
***********************************
EQUATIONS 1
@temp(Out, TCollOut) = [28,1]
***********************************
** outputs to other ddck
***********************************
******************************************************************************************
** outputs to energy balance in kWh and ABSOLUTE value
** Following this naming standard :
** qSysIn_name, qSysOut_name, elSysIn_name, elSysOut_name
******************************************************************************************
EQUATIONS 1
qSysIn_Collector = PColl_kW
***********************************
** Dependencies with other ddck
***********************************
EQUATIONS 1
pumpColOn = puColOn
CONSTANTS 2
C_tilt = slopeSurfUser_1 ! @dependencyDdck Collector tilt angle / slope [°]
C_azim = aziSurfUSer_1 ! @dependencyDdck Collector azimuth (0:s, 90:w, 270: e) [°]
EQUATIONS 4
**surface-8
IT_Coll_kJhm2 = IT_surfUser_1 ! Incident total radiation on collector plane, kJ/hm2
IB_Coll_kJhm2 = IB_surfUser_1 ! incident beam radiation on collector plane, kJ/hm2
ID_Coll_kJhm2 = ID_surfUser_1 ! diffuse and ground reflected irradiance on collector tilt
AI_Coll = AI_surfUser_1 ! incident angle on collector plane, °
EQUATIONS 5
IT_Coll_kW = IT_Coll_kJhm2/3600 ! Incident total radiation on collector plane, kW/m2
IB_Coll_kW = IB_Coll_kJhm2/3600 ! incident beam radiation on collector plane, kW/m2
ID_Coll_kW = ID_Coll_kJhm2/3600 ! diffuse and ground reflected irradiance on collector tilt (kW/m2)
IT_Coll_Wm2 = IT_surfUser_1/3.6
IT_Coll_kWm2 = IT_surfUser_1/3600
***********************************
** Begin CONSTANTS
***********************************
CONSTANTS 3
MfrCPriSpec = 15 ! Coll. Prim. loop spec. mass flow [kg/hm2]
AcollAp = 5 ! Collector area
MfrCPriNom = MfrCPriSpec*AcollAp
***********************************
** Begin TYPE
***********************************
UNIT 28 TYPE 1
PARAMETERS 11
nSeries ! number in series
AcollAp ! collector area
cpBri ! fluid specific heat kj(kgK
efficiencyMode ! efficiency mode
testedMfr ! tested flow rate kg/(hm2)
Eta0 ! intercept efficiency
a1 ! efficiency slope kJ/hm^2K
a2 ! efficiency curvature kJ/hm^2K^2
2 ! optical mode
FirstOrderIAM ! 1st order IAM
SecondOrderIAM ! 2nd order IAM
INPUTS 9
TCollIn
MfrColl
Tamb
IT_Coll_kJhm2
IT_H
ID_Coll_kJhm2
0,0
AI_Coll !Flo check ! JS: This was defined wrong before (C_azim, even though it is incident angle input). Now it should be correct.
C_tilt !Flo check ! JS: This should be correct
*** INITIAL INPUT VALUES
20 0 10 0 0 0 GroundReflectance 45 0
EQUATIONS 4
**MfrCout = [700,2]
Pcoll = [28,3] !kJ/h
PColl_kW = Pcoll/3600
PColl_kWm2 = PColl_kW/(AcollAp+1e-30)
PColl_Wm2 = PColl_kWm2*1000
***********************************
** Monthly printer
***********************************
CONSTANTS 1
unitPrintSol = 31
ASSIGN temp\SOLAR_MO.Prt unitPrintSol
UNIT 32 TYPE 46
PARAMETERS 6
unitPrintSol ! 1: Logical unit number, -
-1 ! 2: Logical unit for monthly summaries, -
1 ! 3: Relative or absolute start time. 0: print at time intervals relative to the simulation start time. 1: print at absolute time intervals. No effect for monthly integrations
-1 ! 4: Printing & integrating interval, h. -1 for monthly integration
1 ! 5: Number of inputs to avoid integration, -
1 ! 6: Output number to avoid integration
INPUTS 4
Time Pcoll_kW PColl_kWm2 IT_Coll_kWm2
**
Time Pcoll_kW PColl_kWm2 IT_Coll_kWm2
***********************************
** Hourly printer
***********************************
CONSTANTS 1
unitHourlyCol = 33
ASSIGN temp\SOLAR_HR.Prt unitHourlyCol
UNIT 34 TYPE 46 ! Printegrator Monthly Values for System
PARAMETERS 7
unitHourlyCol ! 1: Logical unit number, -
-1 ! 2: Logical unit for monthly summaries, -
1 ! 3: Relative or absolute start time. 0: print at time intervals relative to the simulation start time. 1: print at absolute time intervals. No effect for monthly integrations
1 ! 4: Printing & integrating interval, h. -1 for monthly integration
2 ! 5: Number of inputs to avoid integration, -
4 ! 6: Output number to avoid integration
5 ! 7: Output number to avoid integration
INPUTS 6
Pcoll_kW PColl_kWm2 IT_Coll_kWm2 TCollOut TCollIn MfrColl
**
Pcoll_kW PColl_kWm2 IT_Coll_kWm2 TCollOut TCollIn MfrColl
***********************************
** Online Plotter
***********************************
UNIT 103 TYPE 65 !Changed automatically
PARAMETERS 12
4 ! 1: Nb. of left-axis variables
2 ! 2: Nb. of right-axis variables
0 ! 3: Left axis minimum
10 ! 4: Left axis maximum
0 ! 5: Right axis minimum
100 ! 6: Right axis maximum
nPlotsPerSim ! 7: Number of plots per simulation
12 ! 8: X-axis gridpoints
1 ! 9: Shut off Online w/o removing
-1 ! 10: Logical unit for output file
0 ! 11: Output file units
0 ! 12: Output file delimiter
INPUTS 6
Pcoll_kW PColl_kWm2 IT_Coll_kWm2 MfrColl
TCollOut TCollIn
Pcoll_kW PColl_kWm2 IT_Coll_kWm2 MfrColl
TCollOut TCollIn
LABELS 3
Power_and_Mfr
Temperatures
Collector
*******************************
**END Type1.ddck
*******************************