Model Messages
The model messages refer to the model building, the components, and their input values. They appear from Log level 2 Default.
Message 8500—Steam Outlet State Unknown
The steam state is unknown. Please check whether you have forgotten to use a State Determination component.
Message 8501—Isentropic Efficiency
The isentropic efficiency is greater than 1. Please check the plausibility of the steam states.
Message 8502 a—Outlet Temperature Below Inlet Temperature
Check input: The outlet temperature must be higher than the inlet temperature (cold consumer, heat generator). Please check all temperatures in the Technical Input Data of the components and the correct connection of supply and return flow in the circuit.
Message 8502 b—Inlet Temperature Below Outlet Temperature
Check input: The inlet temperature must be higher than the outlet temperature (heat consumer, chiller). Please check all temperatures in the Technical Input Data of the components and the correct connection of supply and return flow in the circuit.
Message 8503—Storage Is Not Used
The storage is not used. You may have to specify a loading strategy or operate the system with look-ahead.
Description
The storage is not being loaded. This does not have to be an error: there may not be any excess energy, the use of the storage is not worthwhile, or other restrictions affect the system.
Normally, however, the storage should be operated. To do this, the corresponding loading strategy must be specified.
Message 8504—Side Condition Not Considered in Structural Optimization
The operational side condition cannot be taken into account during structural optimization. It is integrated again in the subsequent operational optimization.
Message 8505—Look-Ahead Time Frames Not Specified
No time frames are specified for the simulation. This can lead to serious errors in the simulation results.
Description
Please specify the time frames for the calculation and for the results.
Message 8506—Structural Optimization With Cogeneration Tariff Component
In the component Electricity_Tariff_CHP_Surcharge, you have selected a structural optimization component. This works only with compensation according to tender. Select ‘Greater 2 [MW_el] to 50 [MW_el]’ as the size of this CHP and enter an estimated value as the compensation.
Message 8507—Wrong Dimensoning
At the nominal point, the power generated exceeds the drive power. Please verify the plausibility of the input data.
Message 8508—Wrong Characteristic Curve
Die Nennleistung/maximale Fläche The nominal power/maximum area/nominal volume flow/nominal mass flow is outside the investment/reinvestment cost function. Please add the missing values to the investment/reinvestment cost function.
or
The investment/reinvestment cost function should be completed to 0.
or
Missing input in diagram: The characteristic curve has to start with the value zero.
or
Missing input in diagram: The input power (x-axis) of both diagrams must cover the same range of values.
Message 8509—Wrong Dimensioning
The power output in nominal operation is less than the sum of the nominal driving power (COP/EER must be greater than 1). Please verify the plausibility of the input data.
Message 8510—Error CHP Input
The inserted CHP size does not match with the selected CHP.
Message 8512—No Look-Ahead Used for the Operating Time Parameters
You are using no simulation time frame. Operation time parameters may not be used properly. In the simulation ribbon, change the simulation time frame (look-ahead) to a value at least as large as the operation time parameter.
Message 8513—Wrong Investment Cost Function Structural Optimization
The maximum possible nominal power/maximum area/nominal volume flow/nominal mass flow is outside the investment cost function. This way, the maximum size is restricted in the investment cost function.
Message 8514—Structural Optimization Without Cost Function
You have not specified any investment cost function. Therefore, the structural optimization calculates the optimal nominal capacity of the component without taking investment costs into account. If you want to consider investment costs in the structural optimization, add an investment cost function under the economic input data and restart the simulation.
Message 8516—Characteristic Curve of the Heat Pump Cannot be Utilized for the Value
The source supply temperature is outside the value range of the characteristic curve COP vs. source supply temperature or maximum thermal power vs. source supply temperature. In the simulation, the nearest valid value is assumed for the COP or the maximum thermal power.
Message 8517—Error in the Energy Balance of the Fuel Cell
The energy used exceeds the energy provided. Verify the nominal electrical and thermal capacity and fuel utilization.
Message 8518—Warning of Too Large Big-M
The value of the Big-M is 1000 times larger than the maximum value of the variables occurring with it in the equation context. This is numerically unfavorable and should be adjusted in the component.
or:
The value of the Big-M is wrongly reached by a variable occurring in the equation context. Increase the value of the Big-M, because the condition of the control component is not fulfilled this way.
Message 8519—Error in the Control
You use an output variable as input in an extended control. Because of the calculation sequence, this output variable cannot be determined before it is required in the control.
Further information
Understanding the hybrid model equations is a prerequisite for using the correct variables to model a programmable control.
Message 8520 a—Error in Steam Heat Transfer
Additional heat is required in the component to equalize the energy balance. Reparametrize the corresponding steam states and ensure that the heat exchangers are connected in series.
Further information
If two steam Heat transfer componts are connected in series (e.g., for preheating or reheating), the energy balance is overdetermined by the specification of all steam states. In this case, it is necessary to check the Series connection steam-to-steam checkbox in the heat exchanger Heat_Extraction_From_Steam. A loss or gain flow is then calculated internally and displayed in the Output data. If it is a loss flow, a warning is only issued if the flow is greater than 5 % of the total heat. If additional energy is generated in the component, an error message is issued, as it is assumed that the parameterization is then incorrect.
Message 8520 b—Warning in Steam Heat Transfer
High heat losses occur in the component in order to equalize the energy balance. Check the parameterization of the corresponding steam conditions and ensure that the heat exchangers are connected in series.
Further information
See Message 8520 a
Message 8521—Warning on the Composition of the Incoming Fuel
The incoming fuel is not pure hydrogen. However, the calculation assumes that pure hydrogen is available for methanol synthesis.
Further information
The Output data for methanol synthesis are based on thermodynamic calculations of the individual process steps. The material data and parameters used for this are based on the assumption that the incoming fuel consists of pure hydrogen.
Message 8522—Structural Optimization Without Investment-Dependent Costs
Because neither an investment cost function nor specific investment costs are specified, the optimal nominal capacity of the component is determined in structural optimization independently of cost.
Further information
You have not specified an Investment cost function or Specific investment costs. Therefore, the structural optimization calculates the optimal nominal capacity of the component without taking investment costs into account. If you want to consider investment costs in the structural optimization, add an Investment cost function or Specific investment costs under the Economic input data and restart the simulation.
Message 8523—Model Error in the Component …
Mixing fuel streams can lead to errors in the calculation. In this case please use the component fuel mixer.
Further information
With the material model Fuel Considering composition, different fuel streams must not be connected without the Fuel_Mixer component. Please note the information on the material model in the Fuel Special Features article.
Message 8524—Estimated Supply
The deviation between Estimated supply and actual consumption is too high. Check the Estimated supply in the Input data of the tariff component. A more precise consumption estimate improves the quality of the optimization results. Use the time series of the Integrated consumption from the Output data as Input data for the Estimated supply if applicable. Restart the Simulation afterwards.
Further Information
Please also note the information in the article Estimated Input Data.
Message 8525—Inaccuracies in Energy Demand Costs With Demand Peak Optimization
You are using the item Energy demand costs with peak load optimization with the Reference period of one Year in combination with a compression level. This may lead to unsolvable time steps. Set the compression level to exact to avoid this issue.
Further Information
Please also note the information in the article Tariff Components.
Message 8526—Neglecting Energy Demand Costs With Demand Peak Optimization
Because of the selected compression level, the monthly Energy demand costs with peak load optimization are not considered in the simplified pre-stage, e.g., in structural optimization for calculating the optimal plant sizes. Set the compression level to No compression/exactly to take these costs into account.
Further Information
Please also note the information in the article Tariff Components.
Could Not Load File From DWD/PVGIS
If the weather data import from the DWD/PVGIS does not work, this can have different causes. Check your Internet and firewall settings. If the DWD is not available, you can wait until the DWD has repaired the interface or log in to the DWD directly at https://kunden.dwd.de/obt/?lang=en with your account and download the data from there.
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