Project: Optimization of Thermal Battery Design Using Phase Change Materials
Abstract:
This project aimed to design a thermal battery utilising phase change material, incorporating thermodynamic, material selection, financial risk analysis, and thermal conductor design considerations. Through iterative refinement using CAD software and mathematical modelling tools, an optimised design in terms of cost and effectiveness was obtained.
Project Statement:
The goal of this was to design a reliable and efficient thermal battery system (aka a Latent Heat Storage System) that utilises phase change materials (PCMs) as a primary heat storage medium. The system would be primarily powered by a ground source heat pump, operating under the tarmac car park of a commercial business. With increasing demand for renewable energy sources and portable power solutions, optimising thermal battery designs was considered to be an area where gains could be made to improve building efficiency and reduce power consumption.
Results:
After conducting extensive research on various PCM types and their properties, I selected a suitable material combination for this project, electing to utilise organic fatty acids. The CAD design of the system was created using Autodesk Inventor, incorporating 3D printing as a prototyping method to validate the proof of concept.
Simulation:
Using R-studio, I developed a comprehensive simulation model to calculate thermal losses within the battery, alongside the commercial property it was designed for. The model took into account various factors such as:
Material properties (e.g., specific heat capacity, thermal conductivity)
Heat transfer coefficients, convective resistance, and impact of phase-change on heat transfer.
Battery geometry and configuration
Solar radiance to the ground-source heat pump and effective transfer.
Heat loss in transportation and building operation.
The simulated model was able to predict thermal losses across different temperature ranges, providing insight into the required extra load to reach and maintain a usable target temperature for the commercial setting. This allowed for a more informed approach to design iteration and improvement.
Heat Exchanger Design:
To address the challenge of achieving efficient heat dissipation, I employed a multi-layered heat exchanger design. This approach involved:
Selecting suitable material properties and geometries to maximise PCM exposure during different stages of phase change
Optimising layer thicknesses to minimise thermal resistance
Incorporating additional thermal interfaces and radiation barriers
The thermal conductor design significantly reduced thermal losses, improving the efficiency of the system greatly.
Discussion:
While this project has demonstrated the potential of phase change materials in thermal battery applications, there are areas for improvement. Firstly, utilising more robust simulation software like fluidWorks would have provided a more robust understanding of thermal losses and heat transfer mechanisms. This could have enabled the development of a more accurate and reliable design.
Lastly, further research into exploring other PCM types and optimising their performance would allow for a more robust product. Many PCMs are proprietary and not readily available, and so sourcing information requires collaboration with numerous different companies. Integrating these advancements into future projects could greatly increase the robustness of the result, and a more reliable product.
Conclusion:
This project showcases my ability to apply mathematical modelling tools (R-studio) and CAD software (Autodesk Inventor) to optimize thermal battery design using phase change materials. It also exemplified my understanding of design processes and iterative refinement. I utilised knowledge and understanding of wider engineering principles such as thermodynamics, material science, and software development.
Working on this project as a mechanical design engineer provided me an opportunity to work in an atypical field and apply my theoretical knowledge to a practical setting. In particular the skills developed through software development for this project will be valuable assets in future projects where complex mathematical models are involved.
