thermo-simulation

Authored by Wyatt Sullivan for an interview, this project is a solar thermal energy transfer simulation with a React/HTML/CSS frontend and Node.js/Express backend. This software runs locally, and is intended to simulate a solar collector connected to a water tank by pipes powered by a pump. The simulation allows many different configurations, giving the user freedom to tamper with parameters such as the specific heat capacity of the fluid, solar panel efficiency and size, cloud cover, ambient temperatures, starting temperatures of the tank and fluid, etc. The user set these parameters at the beginning of the simulation and/or change them as time goes on throughout the simulation, allowing for dynamic analysis. The main thermodynamics equations used are the Hottel-Whillier-Bliss equation (from Beckham & Duffie's "Solar Engineering of Thermal Processes"), and the heat transfer equation: Q = m * c_p * ΔT

Prerequisites

• Node.js (v14 or later)
• npm (usually comes with Node.js), for installing dependencies
• Git (optional, for cloning the repository)
• A modern web browser (e.g., Chrome, Firefox, Safari)
• Ports 3000 and 3001 available on your machine

Getting Started

1. Clone or download the repository:

   git clone https://github.com/wyasul/thermo-simulation.git
   cd thermo-simulation
   

   or download at: https://github.com/wyasul/thermo-simulation

2. Install dependencies for the backend and frontend (make sure you're in root directory):

   npm install
   

Running the Application

1. In the project root directory, run:

   npm start
   

   This will start both the backend server (on http://localhost:3001) and the frontend development server (on http://localhost:3000)

2. Open your browser and navigate to http://localhost:3000 to view the application.

Running the Simulation

1. After starting the application, navigate to http://localhost:3000 in your browser.

2. View default simulation / reset initial parameters:

   • The interface will show the simulation with default parameters. You can view the simulation in real time by dragging the sliding bar under 'Timeline View', or you can analyze the 'Table View' of the simulation, which will give an hour-by-hour breakdown in the changes of temperatures.
   • If you desire, you can adjust input fields to configure the start state of the simulation (e.g., panel size, fluid properties, tank volume).
   • For each paramater edit, click out of the box or press 'Enter' to save the paramater for the simulation, and the simulation will re-run

3. Interact during simulation:

   • You can drag the sliding bar to a specific hour, then modify parameters to your liking, such as cloud cover or maximum ambient temp, to simulate a dynamic real-world scenario.
   • For example, you could start with default params, slide the bar to hour 12 (12pm), then change cloud cover from 0 to 40% to simulate a shift in weather. You could also shift the min or max temperatures, or even set your own fixed temperature and continue to change it hour by hour.
   • In timeline view, changes to the parameters will display in the Change log at the top right, explaining what parameter changed, and when it changed. In table view, the details of your changes will appear in the rows corresponding to when the change was made.

4. Analyze results:

   • Use the timeline view diagram to examine temperature trends over time
   • Alternatively, you can view a breakdown of changes in temperature of all components within table view.

5. Reset or adjust:

   • Click "Reset" to start over with the default parameters.
   • Or continue modifying the ongoing simulation to explore different scenarios.
   • By default, the simulation starts at midnight (hour 0). Changing the start hour has been disabled. To simulate a different start hour, you can tune parameters at hour 0 in such a way that an desired "starting state" is reached by the hour that you wish the simulation to begin with.

Running the Tests

To run all tests:

npm test

This will run backend tests.

The tests are designed to thoroughly evaluate each thermodynamics function within the file calculations.js. There are 5 functions:

1. getSolarIrradiance: Calculates the solar irradiance based on the time of day and cloud cover, using a simplified model involving a cosine wave with fixed sunrise and sunset times.
2. calculatePanelUsefulEnergyGain: Determines the useful energy gain of a solar panel using the Hottel-Whillier-Bliss equation, considering factors like solar irradiance, panel efficiency, and heat loss.
3. calculateHeatTransferToFluid: Computes the heat transfer to the fluid and the resulting temperatures in the solar panel, based on equations from chapter 6.9 in Beckham & Duffie.
4. calculateHeatTransferToTank: Calculates the heat transfer from the solar panel fluid to the storage tank and updates the tank temperature using standard heat transfer equation, considering pump power and fluid properties.
5. simulateTemperature: The main simulation function that uses the above functions to calculate temperature changes in a solar panel system over a specified duration, accounting for various input parameters and changes over time.

Each of these functions is tested with various input parameters. Most tests ensure that each function does what it is intended to do in static state. Some tests reproduce changes to the variables over time and compare simulation results. There are also a couple tests that reproduce situations found in the Beckham and Duffie textbook, acting as a sort of 'ground truth'. Keep in mind, many simplifications in thermodynamics are assumed, for the sake of clarity and avoiding complexity.

Project Structure

• backend/: Contains the Express server and simulation logic
• frontend/: Contains the React application
• backend/__tests__/: Contains backend tests

Additional Notes

• The backend runs on port 3001 by default
• The frontend runs on port 3000 by default
• Make sure both ports are available on your machine

Troubleshooting

If you encounter any issues while setting up or running the application, please check the following:

1. Ensure you have the correct versions of Node.js and npm installed.
2. Make sure all dependencies are properly installed by running npm install in the root directory
3. Check that ports 3000 and 3001 are not being used by other applications on your machine.

If problems persist, please email wyattsullivan02@gmail.com, or text 307-699-2974.

Acknowlegements

• The logic behind the thermodynamics code is drawn from Beckham & Duffie's "Solar Engineering of Thermal Processes" textbook. All thermal equations used can be found in Chapter 6, particularly sections 6.7 and 6.9