Group 073-10: Efficient Heat Pipes for Small Scale Industrial/Commercial Applications

This week, prototype 3 and 4 were constructed and tested. As shown in the image below, the shorter one, prototype 4, has a length of 1 foot and the longer one, prototype 3, has a length of 2 feet. The effect of the length of the heat pipe on its efficiency is tested this week. Below is the tables and graphs of the testing done in lab this week. From the test results, it can be concluded that prototype 4 performed better than prototype 3. In 240 seconds, prototype 4 had a temperature increase of 12 degrees, while prototype 3 increased only 2 degrees. A possible reason is that the because the prototype 3 is longer in length, and so heat transfer takes longer. It is also possible due to heat loss along the length of the heat pipe.

Some new design considerations were taken into account in order to test a proposed idea with smaller diameter heat pipes. After doing some basic research it was determined that capillary action has a greater effect the smaller your system gets. Larger diameter heat pipes will still experience capillary action but other factors such as gravity will have different effects on how the working fluid flows in the wick. The diagram in Figure 1 illustrates the proposed problem with larger diameter heat pipes compared to their smaller counterparts. Figure 1: Large and Small Heat Pipe Capillary Force Comparison By reducing the pipe diameter to half of Prototypes 1 and 2, capillary action should be able to happen more efficiently due to surface tension and lower liquid weight (less volume in a smaller pipe). Gravitational effects overcoming surface tension demonstrated in Figure 1 is why we believe that a smaller heat pipe would theoretically run more efficiently. Furthermore, as tempera...

During week 3, the team built and tested the first two prototypes of the heat pipe. The construction of the heat pipes was straightforward as these two prototypes had very little complexity to them. A process of rapid prototyping was utilized to come up with two working devices that would be able to obtain useful data for quick design iterations. Below are two construction photos of the first heat pipe. The first image shows the interior mesh used as a wick and the bottom picture is the crimped pipe end before soldering. A detailed construction log can be viewed on the Heat Pipe Fabrication page. Testing The testing involved using a clamp to hold the pipe in place while hot air was applied to one of the ends of the pipe. Two thermocouple probes were used to measure the change in temperature of the ends of the heat pipe over time. A picture of the apparatus used is shown below: The results for the first prototype show that it was relatively inefficient, due to the fact...

In week 2, the team discussed the timeline and final deliverables of this project. Project Timeline The project timeline is shown below in Table 1. Table 1: Project Timeline The main tasks of the project include research, initial design, ordering of material, generation of a CAD model, construction, testing, design optimization and the final report preparation stage. Research will be done throughout the first few weeks to aid the design, simulation and construction processes. Components are ordered this week, and it will take on average a few days to a week to arrive. We have started to build the CAD model using Autodesk Fusion 360 and Solidworks software. For the construction and testing phase, two prototypes and one final model will be built in the course of six weeks. The first prototype will be constructed in week 3, and tested in week 4. Then, the second prototype will be made in week 5 and tested in week 6. The final model of the heat pipe will be made i...

The primary focus of week 1 was to research the existing designs of a heat pipe, understand the mechanisms at which they operate, and come up with ideas to build an efficient low temperature heat pipe. The main purpose of the heat pipe is to transfer heat from one place to another. Research was conducted on low-temperature applications and the advantage and disadvantage of different designs. After analyzing the information and taking into account the time and budget restriction for this project, an initial design of the heat pipe was generated.  The heat pipe will be made of copper tubing with mesh inside the tubes to serve as a wick. There will also be Aluminum heatsink fins at the condenser end to increase surface area for the spreading of heat to the surrounding. The main tasks include research, initial design, ordering of material, generation of CAD model, construction, testing, and optimization. The design and construction of the heat pipe are limited to a budget of $400 ...