Final Presentation

We capped the semester off by presenting the cooler in the BYU - Idaho Capstone open house. It was a lot of fun to show off the cooler and teach people about the technology we used. There aren't very many people who understand how a thermoelectric module works.

It has been a relief to be done with the cooler although I do miss the excitement of trying to continually improve the concept. We'll see what changes may come about in the future.....

Displaying additional thermoelectric modules and we even filled a small container with dry ice to demonstrate how a thermoelectric module can be used as a thermoelectric generator to produce electricity.
Displaying step-by-step pictures of our cooler building process
The final product...

Cooler Testing: Dry ice leak test

I used hot water and dry ice to fill the chamber with vapor. The hope was that after shutting the lid the vapor would show us if we had any leaks.

If you look hard you can see vapor pouring out of the bottom of the hot air exhaust vent. This is not necessarily a good thing.... haha. This was only happening on one side of the cooler. I am assuming this is due to the fact that we replaced the module on that side. In the process of replacing the module we must not have sealed the foam together as well as we should have. We'll know better next time.

Hayden and I having fun with the dry ice. We couldn't resist but have a little fun with the left over dry ice.

After completing this test we conclude that the cooler as failed the leak test.

The test specifications required the cooler to be completely air tight. The ironic information that the test provided is that the lid sealed very well. It sealed tight even after our "slight" modifications.

Finished Product

Testing the solar panel: I tested the voltage coming out of the panel and we were at right around 22 volts. This feeds into the charge controller and then charges the batter at 12 volts.

Side View: Here the black weather stripping is visible. The black actually adds a nice accent to the white cooler.

We placed the final acrylic section into the lid this afternoon.

We finally finished the modifications on the cooler this afternoon. We placed a piece of black weather stripping along the front side to help seal the lid tight. We also placed the last piece of acrylic into the lid. All in all it looks really good and turned out better than we expected.

Solar Powered Cooler Thermal Imaging Test

In order to better understand where our possible losses were occurring we needed a thermal imaging camera. The local Rexburg Police Department was kind enough come take some pictures for us with their camera. Interestingly enough our loss are occurring in areas in which we would have never guessed!

Although it may be too late in the game to make any changes to correct these areas it has been very helpful to understand how and where we can improve on our design.



Image 1: This is a front view of the Igloo cooler with the lid shut. The bright points are "hot" points on the picture (relatively speaking). The dark areas or the cold points. We had the lid cracked just a bit as to allow the dry ice the ability to escape without popping our lid off. For that reason you can see the area around the lid is almost black. Also, the bright spots towards the top of the lid are simply hand prints from people opening it up. The point of interest in this image is the dark square on top of the lid. In the original cooler that is a simple access lid which allows you to open up a smaller lid grab your soda pop out of whatever instead of having to open up the entire lid. Well, that access point happens to be hollow plastic! We have sealed in the back side of that lid with foam but the lid itself remains hollow. You can see the impact that the lack of internal insulation has on the actual heat transfer through the lid.

Thermal Image 2: This is a side shot showing the fan, 2 hot air exhaust ports, and discharge spout. From this angle you can again see the dark square on the lid. You can also see the hot air exhaust ports are bright white. The fan appears the same probably because the heat sync sits right behind the fan. We're actually seeing the heat sync rather than the fan. The most interesting item in this shot is the discharge plug underneath the fan (It is hard to see in this image). The discharge plug is almost black! Similarly to the small access point on the lid this plug has been foamed in.

Solar-Powered Cooler Acrylic Box

This is just a quick update on the housing process. We finished caulking in the reaming portion of the box. We still need to mount our acrylic housing on the lid portion.

Completed Acrylic Housing

Inside view of acrylic box w/ visible thermocouple.

Testing update

This is data we gathered last night from our "maiden voyage". We ran the cooler all night off of a 12 - volt car battery. We also a battery charger wired to the battery as to not completely kill the it off. The initial box temperature was at 66 degrees F. Our original set point for the interior box temperature was 35 degrees F. It hit that set point in 2 hours (15 degrees/hour). I then lowered the set point to 32 degrees F. It quickly brought the temperature down to 32 degrees F where it continued to maintain that temp throughout the night. The bumps in the graph above represent the point at which the box temp has it the set point. At that time the modules turn off. When the box temp again rises above the set point the modules kick on to bring it back down.

The next task is to determine how well it will function with only one module running rather than two. This is especially important because when the solar-panel is connected only one module will be running. We'll see.....