GHEtool 2.0.0

Python package for borefield sizing

GHEtool: A open-source tool for borefield sizing in Python

What is GHEtool?

GHEtool is a python package that contains all the functionalities needed to deal with borefield design. It is developed for both researchers and practitioners. The core of this package is the automated sizing of borefield under different conditions. The sizing of a borefield is typically slow due to the high complexity of the mathematical background. Because this tool has a lot of precalculated data (cf. infra), GHEtool can size a borefield in the order of tenths of milliseconds. This sizing typically takes the order of minutes. Therefore, this tool is suited for being implemented in typical workflows where iterations are required.

GHEtool also comes with a graphical user interface (GUI). This GUI is prebuilt as an exe-file because this provides access to all the functionalities without coding. A setup to install the GUI at the user-defined place is also implemented and available here. This graphical interface is made by Tobias Blanke from FH Aachen.

Functionalities

GHEtool offers functionalities of value to all different disciplines working with borefields. The features are available both in the code environment and in the GUI. These features are:

• Sizing the borefield (i.e. calculating the required depth) for a given injection and extraction load for the borefield (two sizing methods are available). The tool can work with monthly and hourly load profiles
• Finding the optimal rectangular borefield configuration for a given heating and cooling load
• Optimising the load profile for a given heating and cooling load
• Using dynamically calculated borehole thermal resistance
• Calculating the temperature evolution of the ground for a given building load and borefield configuration
• Importing heating and cooling loads from *.csv and *.xlsx files
• Using your custom borefield configuration

In the example and validation folder, one can find information on how to use this functionalities.

Precalculated data

This tool comes with precalculated g-functions for all borefields of type nxm (for 0<n,m<21) for which the boreholes are connected in parallel. For these borefield configurations, the g-functions are calculated for different depth-thermal conductivity-spacing combinations. The ranges are:

• Depth: 25 - 350m in increments of 25m
• Thermal conductivity of the soil: 1 - 4 in increments of 0.5W/mk
• Spacings (equal): 3 - 9m in increments of 1m

Here a burial depth (D) of 4.0m is assumed even as a borehole radius of 7.5cm for all the precalculated data.

It is possible to calculate your own dataset to your specific project based on the pygfunction tool and use this one in the code.

Requirements

This code is tested with Python 3.9 and requires the following libraries (the versions mentioned are the ones with which the code is tested)

• Numpy (>=1.20.2)
• Scipy (>=1.6.2)
• Matplotlib (>=3.4.1)
• Pygfunction (>=1.1.2)
• Tkinter (>=0.1.0)
• Openpyxl (>=3.0.7)
• Pandas (>=1.2.4)

For the GUI

• PyQt5 (>=5.10)

Quick start

One can install GHEtool by running Pip and running the command

pip install GHEtool

Developers can clone this repository.

License

GHEtool is licensed under the terms of the 3-clause BSD-license. See GHEtool license.

Contributing to GHEtool

You can report bugs and propose enhancements on the issue tracker. If you want to add new features and contribute to the code, please contact Wouter Peere ([e-mail]).

Main contributors

Wouter Peere, KU Leuven & Boydens Engineering (part of Sweco), [e-mail].

Tobias Blanke, Solar-Institute Jülich, FH Aachen, [e-mail]

References

Cimmino, M. (2018). pygfunction: an open-source toolbox for the evaluation of thermal response factors for geothermal borehole fields. In Proceedings of eSim 2018, the 10th conference of IBPSA- Canada. Montréal, QC, Canada, May 9-10.

Peere, W., Picard, D., Cupeiro Figueroa, I., Boydens, W., and Helsen, L. Validated combined first and last year borefield sizing methodology. In Proceedings of International Building Simulation Conference 2021 (2021). Brugge (Belgium), 1-3 September 2021.