We've been working on new prototypes to improve performance and apply lessons learned from our
. Check out some of the improvements and changes:
Scrappy Prototype vs. Version 2 Design
We're pursing a more open, clean design based on lessons we've learned building and testing our Version 1 prototypes. This updated design, pictured at right, would be easiest to manufacture using casting processes, CNC machining, or a combination of the two. These are expensive, capital intensive processes.
During the prototyping phase, we need to be able to test the functionality of our design language quickly and with few resources. That need has led to us building 'scrappy' prototypes. These prototypes accurately mimic the behavior of the Version 2 design (pictured at right), but cost significantly less money and time to produce. This lets us validate, modify, or reject our theories and more wisely invest our resources as we move forward.
Because of the fact that our devices must withstand heat, 3D printing methods aren't appropriate to construct our prototypes. With Version 2, we've gone to an aluminum chassis in addition to the aluminum base plate and heat sink. Therefore our prototype was built using a desktop manual lathe and mill, plus a variety of hand tools. The finished result doesn't look exactly like the designs we've created in 3D CAD software, but it will operate the same.
All-Aluminum Construction
These new prototypes are built entirely from aluminum, from the base plate up through the heat sink. This improves the weight, durability, and feel of the device which gets us closer to production-level quality.
However, it adds two large challenges: keeping the device cool enough to handle over long periods of time and preventing thermal short circuits which would cause all the heat from the source to by-pass our TEG's and go directly to the 'cool side' of the device. This would kill put undue stress on our cooling system and hamper our ability to create a good temperature difference across the device, which is crucial for thermoelectrics to function. The benefit of all-aluminum construction is worth the added challenge, however, and we've added a number of high-resistance thermal breaks throughout the device to direct heat flow where we want it to go.
Improved Cooling
The more open layout of the device should allow for better cooling along the entire length of our cooling tower. We're also still experimenting with more advanced configurations of this cooling tower, incorporating a variety of materials and media. Early tests show that a mix of different media give the best performance curve over a long period of time. Another improvement of this prototype over the original is that we are able to easily swap out our cooling system, allowing more configurations to be tested.
Electrical System Test
You can see the two wires sticking out of the side of this prototype. Those are the raw output from our thermoelectric system. They tie into our electrical system, which we currently house separately from the main device. This lets us easily make measurements, tweaks, and improvements while we're optimizing the system.
While the electrical system has been separately bench tested and run a number of times on our Version 1 prototypes, we hope to see marked improvement in output on this new prototype both due to improvements on the mechanical side, as well as optimizations and miniaturization on the electrical side.
After validation of the electrical system and mechanical systems, we plan to incorporate them. In fact, our CAD models already feature housing and wiring routes for the system.
Moving Forward
This new prototype brings us closer to our goal of having a device that is ready to share with friends and testers. An in-depth test series will show us next steps that we need to take, but we hope to start building more of these in mid-2014. Until next time, happy building and
to say hi or follow us
.
- Team Stamp