Portable Drink Cooler

 

Chip Kleinheksel

Summary:

Imagine taking a swig out of drink a beverage minutes after you first opened it, yet it still is at the amazing chilled temperature that it was when it came out of the refrigerator. That would be quite an incredible feat, and due to this, the focus of this design project is to create a personal drink cooler that doesn't just slow the time for the beverage to warm up, but instead keeps the can at a refrigerated temperature (approximately 50 degrees Fahrenheit). Along with this, it is portable thus making it so the refrigerator is basically right at your fingertips at all times.

When creating a product that can fulfill this focus, two options arose. The first option was to create the cooling object using thermoelectric cooling modules, and the other option involved using an endothermic chemical reaction in the form of a packet surrounding the can to keep the can cold. After doing some in-depth analysis on both of these options, the first option was chosen as the better option. This is mainly due to the fact that if the endothermic reaction packet idea was used, a new packet would need to be made for each use, and this seemed to be a disturbance. The first option doesn't involve anything to be recreated before each use other than simply plugging the battery into a charger, thus making this a more optimal product. Choosing the cooling option was the only thing that needed to be considered. After the thermoelectric cooling module option was chosen, ways to power the unit as well as ways to remove the heat created on the hot side of the thermoelectric cooling module were both needed. As for powering the unit, options of using a drill battery power source, regular batteries with a battery holder, and a lantern battery were considered. After doing some analysis and overseeing prices, it was determined that the lantern battery was the best choice because it was more powerful, easier to package, and would last longer than regular batteries, and was much cheaper than a drill battery set up. Also creating the connection between the battery and the unit for the lantern was much more feasible than for the drill battery option. As for removing the excess heat, plain vents, fans, and heat sinks were all considered, and heat sinks were chosen because they removed heat quite well, also they didn't need any power source like a fan and were much cheaper.

After all of the considerations, the final design involved a fabricated piece of aluminum, cylindrical on the inside and squared off on the outside. Four thermoelectric cooling modules were placed on each of the squared off outsides, with a heat sink attached to the outside of each of the modules. The aluminum was squared off on the outside to create a flat surface for the flat modules to come in contact. The area on the aluminum that was covered with the thermoelectric cooling modules was covered with insulation to ensure that the cooled temperature couldn't escape. Attached to the bottom of the fabricated aluminum piece is a piece of bored out wood (4 inches by 4 inches), this encases the battery, and the thermoelectric modules, with the use of wire are connected directly to the battery. The final design can be seen on the following page in figures 1 and 2.

Overall, the design works quite well. The heat sinks do a tremendous job of removing the excess heat created, and the fit between the can and the aluminum is smooth creating great conduction between the cooling module and the can, and therefore making the cooled side conduct very well with the beverage keeping it at a desired cold temperature. The final design stays close to 10 degrees Celsius below the temperature of a bare can when compared over a time span of around 40 minutes for a battery of 6 volts. Given more voltage, the temperature difference would be even better, but for practicality purposes, the 6 volt battery was the best. After 20 minutes, the temperature of can in the cooler is 13 degrees Celsius (55.4 degrees Fahrenheit), which is comparable to the target temperature of around 50 degrees Fahrenheit.