murb_energy_tool

A lightweight energy model based on PHPP and RETScreen. Uses hourly TMY (EPW) files, but data is aggregated into a monthly timestep. Mainly being used during early stage design to understand the minimum thermal envelope performance required given TEDI, TEUI and GHGI targets.

This project includes both a Python library for programmatic use and an interactive Streamlit Web Application for energy modelling. EPW files can be found from local resources or our good friends from Honeybee/Ladybug.

Found Here: https://www.ladybug.tools/epwmap/

Web Application

The interactive web application allows you to easily configure building geometry, windows, envelope, HVAC, and advanced settings to run simulations and generate downloadable reports.

Running the Web App locally

1. Ensure you have installed the requirements (see Installation below).
2. Activate your Python environment.
3. From the root directory of the project, run:

   streamlit run webapp/app.py

4. The web interface will open in your default browser. Upload an EPW weather file, fill in the parameters, and click "Run simulation".

Available Here: https://9s4appx5hvvwlnevx3mtxkj.streamlit.app

Installation

Library (programmatic use) — stdlib only, Python 3.8+

murb_energy_tool is now a pure-Python library with no native dependencies (no numpy, scipy, pandas, or pvlib required). It works in any standard CPython 3.8+ environment, including constrained hosts such as pyRevit's embedded interpreter.

# Clone and add to sys.path — no pip install step needed for library-only use
git clone https://github.com/winterweken/murb
python -c "from murb_energy_tool import test"  # should print "All tests passed"

Web application — additional packages required

The Streamlit web app uses pandas, pvlib, streamlit, and tabulate. Install them with:

pip install -r requirements.txt
streamlit run webapp/app.py

Anaconda users: a conda environment is no longer required for the library. Create a plain venv or use any Python 3.8+ interpreter.

Test the installation

from murb_energy_tool import test

If you see "All tests passed", the library is correctly installed.

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Changes in the pure-Python port

• ISD weather-file support removed. Passing isd_file= to Run() now raises NotImplementedError. Use a TMY EPW file instead (epw_path= or place it in ./input/).
• Library is now embeddable in constrained Python hosts (e.g. pyRevit's embedded CPython) with zero per-machine environment setup.
• Internally, numpy arrays are replaced by a lightweight Vec list subclass; pvlib solar position is replaced by a NOAA NREL SPA implementation; scipy interpolation is replaced by stdlib linear/quadratic interpolation; pandas EPW parsing is replaced by a pure-Python EPW reader.
• Console summaries use tabulate instead of pandas.DataFrame.to_markdown (cosmetic only).

Programmatic Usage

For Python scripting and API usage, see the Jupyter Notebook examples.

To-do

• Below-grade heat transfer
• More precise COPs for heating and cooling plants
• Factor for non-normal irradiance on windows
• Pumps and elevator loads
• Report financial metrics
• Documentation