Heat Exchanger

Final Project for Heat Transfer Laboratory

Spring 2023

Johns Hopkins University

MATLAB Simulation, Soldering and Bending copper tubing, heat exchanger design, perseverance, sealing pressurized systems

Design, fabricate, test, and evaluate a custom heat exchanger to be more effective than a Armfield HT31 heat exchanger testing rig. Preliminary design proposals were evaluated by Baltimore Air Coil (BAC) engineers and the final exchangers were presented to the class.

This project was done in a group with T. DeGuzman, X. Song, and J. Zhong. I led the assembly and fabrication of the exchanger and the filming and compiling of the evaluation videos. Teammates worked on the CAD model and MATLAB Simulation, but all tasks were verified and reviewed in collaboration.

Our initial design was too aggressive on pipe diameter and the standardized motor was not able to pump at the correct speed. Additionally we had issues with sealing our container and preventing leaks. After a redesign with larger pipes (at the cost of bending cleanly), we had a working heat exchanger.

The Armfield heat exchanger removed approximately 540 W of heat while our final design removed 912 W, giving our design a 70% improvement. Ours was also more efficient, and also had twice the overall heat transfer coefficient.

The MATLAB simulation had a predicted value of 1180W removed, compared to our actual 912W. Given the assumptions made to model our complex system, we are pleased with being on the same order of magnitude.

We learned many things in this design project. First, you should always do calculations for components before buying them if planning to use them in a realistic test or prototype. We also learned a lot about sealing, and that a small pressure buildup can lead to a large force on the inside of a container, causing it to burst open. We also learned that using silicone sealant on the inside is far better than on the outside, because the pressure inside the vessels presses the sealant into place instead of trying to push it out. I found this project challenging due to fabrication, sealing issues, and incorrect pipe diameter. We were able to overcome these challenges and quickly redesign to meet our project goals.