Emergency Power Pack
Aluminum-Fuel Based Emergency Power Generator
The Emergency Power Pack (EPP) is a power generator which converts aluminum and water into electricity. The EPP reacts an aluminum fuel with the water in a reaction chamber to produce hydrogen and aluminum hydroxide, a harmless byproduct. It then takes the hydrogen and routes it through a fuel cell connected to a stack of electronics boards. These boards finally convert the erratic output of the fuel cell into a stable, usable output - either in the form of a USB or a motorcycle power connector.
EPP Use Procedure. 1. User inserts yellow lining full of aluminum fuel into a black, fabric reaction chamber. 2. User adds water to the fuel. 3. User screws on the processor. 4. EPP produces usable power and can charge devices.
A user would purchase the yellow inner layer, pre-packed with aluminum fuel, and place the inner layer into the outer fabric housing. Next, they add water to the reaction chamber. Then, they screw on the red and white processor and wait for the aluminum-water reaction to occur. Once power is produced (indicated by an LED at the top of the processor), the user can then plug in either a USB device or an adapter to the motorcycle connector and charge their devices.
Original Enclosure
Original Enclosure Design
The EPP was designed initially for military use to charge conformable wearable batteries, but was later changed to target the consumer market instead as an emergency product. As a result of this shift, the original EPP's processor's enclosure needed to be updated to better fit the new consumer group and to address the technical issues associated with the original design. I focused on designing and creating prototypes for the new enclosure.
The original enclosure's size made it difficult to hold and attach to the reaction chamber. It also packed all of the components too closely together and restricted airflow needed to properly cool off the electronics board. Finally, it was minimal in its user interface and did not provide an intuitive way to use the device.
Of these requirements, I prioritized solving the airflow issue first because it directly hindered the proper operation of the EPP. When the electronics package becomes too warm, it no longer functions properly and stops producing power. I changed the package shape from rectangular to cylindrical to free up space for the boards while also creating a natural air pathway for both the electronics and the fuel cell.
The diameter of the middle of the enclosure was then reduced to create a more comfortable and intuitive grip for the user to screw on the reaction chamber. Three clip-on attachment points were also added to front and back sides to facilitate easy carry and hanging during operation. The first version of this new enclosure was printed on a Form 2 in four pieces and assembled for review.
V1 Enclosure
The V1 Enclosure prototype was used to validate the size and feel of the enclosure. The variation of diameters in the enclosure performed as expected as the skinnier center section drew users to pick it up from the grip. The minimal user interface of an on/off button, a USB and a motorcycle connector on the top of the enclosure were also verified to be sufficient.
Other aspects of the enclosure were revealed to need further work. The walls were thicker than necessary and added too much weight to the overall enclosure. The clip-on attachment points were too close to be useful and not deep enough to fit a carabiner. Internal alignment features took up too much space and made it cumbersome to fit the fuel cell. The air flow configuration prioritized cooling the electronics package but did not provide enough airflow to the fuel cell. There were still many kinks in the design that needed to be worked out.
All of these observations were incorporated into developing a V2 enclosure and the same evaluation process was repeated. Unfortunately, the V2 enclosure did not survive the review process due to the reduced wall strength from the reduction in wall thickness. Regardless, V2 still informed design decisions behind V3, the final prototype.
V3 Enclosure
The V3 Enclosure has three pieces - the front half, the back half, and the lid (not pictured above). The front half is split into three pieces and the back half is split into two in order to fit inside the printer. The two halves are held together at four points with M3 screws and screw-to-expand inserts. The lid is intended to be permanently glued onto the top of the front half after the installation of the electronics package and the fuel cell.
The front half contains all of the major positioning features. The top of the enclosure attaches to a rotating loop, the middle section has a holder to keep the fuel cell in place, and the bottom has a compartment to mount a purge valve from the fuel cell. The bottom of the front half also has a threaded interface which screws on to the reaction chamber. In addition to these features, the sides are covered in vents to ensure ample airflow throughout the enclosure.
In comparison to the complex front half, the back half is simple and is only intended to seal the enclosure closed and protect the components inside.
Due to the time constraints, this enclosure was not able to be tested with the rest of the EPP. Still, all of the components do fit inside and the enclosure does close properly.
In collaboration with Devin Williams, Manuel Castor, Piper Lim, Revanth Damerla, Thomas Needham, and Wesley Cox for 2.014 Engineering Systems Development in Spring of 2017.