The provided scripts implement a workflow for the parametric optimization of a two-phase geothermal source ORC power plant by applying different search algorithms to a TESPy model of an ORC cycle. Besides parameter influence analysis, both single and multivariate, optimization procedures are available.
After downloading install the requirements within a fresh virtual environment:
python -m pip install -r requirements.txtThree different tasks can be accomplished with the software:
- single parameter influence analysis (
from geothermal_orc import single_parameter_influence), - single parameter optimization (
from geothermal_orc import single_optimization) and - multivariate parameter optimization (
from geothermal_orc import multivariate_optimization)
Import the respective functionality and run it with the .json control file. The result date are passed to the function call. Example applications can be found within the scripts folder:
- single.py
- parameter_influence.py
- multivariate.py
Sample input data can be found in the same folder.
Flow diagram of the geothermal ORC plant (a) and Ts-diagram of the process (b)
Please note: You will find all input parameters as well as all equations applied in the models of the example runs in the pdf model report!
The table below highlights the design parameters of the system.
| Item | Parameter | Symbol | Value | Unit |
|---|---|---|---|---|
| Geothermal resource | Steam temperature | Tgs | 140 | °C |
| Steam mass flow rate | ṁgs | 180 | kg/s | |
| Brine temperature | Tgb | 140 | °C | |
| Brine mass flow rate | ṁgb | 20 | kg/s | |
| Steam mass fraction | x | 0.1 | - | |
| Brine/steam pressure | pgeo | 3.615 | bar | |
| Ambient condition | Average temperature | Tam | 5 | °C |
| Average pressure | pam | 0.6 | bar |
| Location | Parameter | Symbol | Value | Unit |
|---|---|---|---|---|
| Turbine | Isentropic efficiency | ηs, t | 90 | % |
| Feed pump | Isentropic efficiency | ηs, fp | 75 | % |
| Air fan | Isentropic efficiency | ηs, af | 60 | % |
| Main condenser | Upper terminal temperature difference | ΔTt, u | 10 | °C |
| Pressure ratio on hot side | pr1 | 1 | - | |
| Pressure ratio on cold side | pr2 | 0.995 | - | |
| Geo-steam evaporator | Pressure ratio on hot side | pr1 | 1 | - |
| Pressure ratio on cold side | pr2 | 1 | - | |
| Geo-brine evaporator | Pinch point temperature difference | ΔTpp | 8 | °C |
| Pressure ratio on hot side | pr1 | 0.98 | - | |
| Pressure ratio on cold side | pr2 | 1 | - | |
| IHE & preheater | Pressure ratio on hot side | pr1 | 0.98 | - |
| Pressure ratio on cold side | pr2 | 0.98 | - | |
| Preheater outlet | Approach point temperature difference | ΔTap | 2 | °C |
| Generator | Efficiency | ηel, mech | 97 | % |
| Motors | Efficiency | ηel, mech | 97 | % |
It is possible to choose the decision variables for the optimization as well as the objective of the optimization. Additionally, other boundary conditions can be specified. Apart from the geosteam share three variables or boundary conditions must be specified in total. Available parameters are listed below:
| Parameter | Meaning |
|---|---|
| p_before_tur | pressure at connection 1 |
| T_before_tur | temperature at connection 1 |
| T_reinjection | temperature at connection 35 |
| brine_evap_Td | temperature change from connection 33 to 34 (negative) |
| Q_brine_ev | heat transferred by brine evaporator |
| dT_air | temperature change from connection 21 to 22 |
| IHE_sizing | IHE sizing factor: 0 = IHE non existent; 1 = maximum heat transfer |
| Q_ihe | heat transferred by IHE |
- It is mandatory to specify the geosteam share.
- For single parameter investigation specify two additional parameters
- For multivariate investigation specify less than two additional parameters
- Specify variable(s) to investigate with upper and lower limit as well as tolerance in case of single optimization
- Specify components, connections and misc for retrieving the respective data in the results DataFrames.
Parameters for misc:
| Parameter | Meaning |
|---|---|
| gross power output | power output of the rankine cycle only |
| thermal efficiency | efficiency considering gross power output |
| net power output | power output including the power required for the condensator's fans |
| net efficiency | efficiency considering net power output |
| IHE sizing factor | IHE sizing factor (see above) |
Choose from:
- "gross power output"
- "net power output"
An archived version of this repository can be found at zenodo: https://zenodo.org/record/5094930. For more information also see the respective publication. A link will be added here once published.
If you have any questions or suggestions feel free to contact us anytime!
Copyright (c) 2022 Francesco Witte, Chaofan Chen
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