Energy Plus Step
Goal
Simulates every building part with EnergyPlus, in order to determine hourly and monthly heating and cooling demands.
EnergyPlus (https://energyplus.net) is a dynamic building energy simulation, with an hourly resolution. Each building part is simulated as one thermal zone, heated and cooled by an ideal system: the results are the sensible ideal loads needed to keep the setpoint temperatures, like DIN V 18599 (no dehumidification).
EnergyPlus 25.1 or newer must be installed, either in its default folder or in the PATH. The newest installed version is used.
- Constructions (material layers) and windows come from the building physics library. U-values (uValue, windowUValue) and g-values defined in the CityGML file are considered: the insulating layer is resized to match the U-value.
- Setpoints, setback temperatures, usage hours and days, air change rates and internal gains come from the building usage library.
- Walls shared with neighbouring buildings are considered adiabatic.
- The weather file is generated from the imported weather data (temperature, irradiances, sky temperature, and wind and humidity if available). Without hourly humidity, a constant relative humidity of 60 % is used. The atmospheric pressure is calculated from the altitude.
Shading by neighbouring buildings is not considered.
The results are stored in a CSV file, with heating and cooling demands per building and per month. A log file lists every simulated or failed building part. The EnergyPlus input and output files can be kept in a separate folder. The step displays maps, a histogram of specific heating demands, and load duration curves for heating and cooling.
Technical information
| Class | EnergyPlusStep |
| Superclass | WorkflowStepWithSimStadtGraphics |
| Author | |
| Maintainer | |
| Source location | simstadt/src/main/java/eu/simstadt/workflowsteps/EnergyPlusStep.java |
| Package | eu.simstadt.workflowsteps |
| Project | simstadt |
Dependencies
- Geometric Estimator Step
- Geometric Preprocessor Step
- Import City Gml
- Physics Preprocessor Step
- Usage Preprocessor Step
- Weather Processor Step
Parameters
Wind-dependent convection (windDependentConvection)
If checked, EnergyPlus calculates the outside convection coefficients from the hourly wind speed.
This requires hourly wind data, e.g. from an hourly Meteonorm (TMY3) weather file: PVGIS and INSEL weather data don't have any.
If unchecked, a constant outside convection coefficient of 20 W/(m²·K) is used, like the surface resistances of EN ISO 6946 and DIN V 18599.
- Type :
boolean - Default :
false - Getter :
isWindDependentConvection() - Setter :
setWindDependentConvection(boolean)
Keep EnergyPlus run folders (keepRunFolders)
If checked, the EnergyPlus input (IDF) and output files of every building part are kept, which is useful to check the simulations.
If unchecked, they are deleted after each simulation, as well as the EnergyPlus weather file (EPW) at the end.
This saves disk space for large districts.
- Type :
boolean - Default :
true - Getter :
isKeepRunFolders() - Setter :
setKeepRunFolders(boolean)