Tuesday, September 22, 2009

You want to build what?

I'm trying to get over some confused looks here in Mbarara as I wander from store to store, asking for strange parts, wood cut to odd dimensions, and joining L-brackets to small blocks of aluminum. I'm trying to build a refrigerator and many folks are a little surprised at that. Understandable - I hesitate a moment before explaining to someone what I'm doing. Even I think I'm a little crazy.

But once I get over my self-consciousness and properly explain what I'm doing, I've been met with a lot of enthusiasm. Several of my suppliers want me to bring in the fridge when I'm done so they can see what all this work is about. They're excited to see something new and unusual.

In case you're wondering, the fridge itself is actually quite simple. It's based on the "Peltier effect" and uses a small cooling module sometimes used in electronics. When an electric current is passed through the module, one side becomes hot and the other cool. Heat is therefore "pumped" from one side to the other.

However, despite its simplicity actually constructing and mounting the equipment has proved difficult with limited resources. I'm learning how to source parts and build from whatever supplies I can find in Mbarara (and occasionally Kampala). For example, today I was explaining to a local metal-worker I wanted to join small L-brackets to a block of aluminum. The purpose of this is to seal the cooling unit off from the inside of the refrigerator, which will be filled with water to help maintain temperature during a power outage. It was a very unusual request, and requires working in aluminum, so he wanted 70,000 UGX ($35). Unfortunately that's way more than I can pay to keep the entire project to a reasonable cost. So now I need to go back to the drawing board - how can I achieve the same goal for a lower cost? It's a process of design iteration.

The purpose of the refrigerator is to demonstrate that a reliable and efficient vaccine cooler can be built in a developing country for low cost. Ideally, the model could be copied in countries all over the world facing the problem of reliably delivering vaccines. This model should be finished in a few weeks and operating in a rural clinic, at which point I will be testing energy use to properly size a solar system to power the unit.

No comments:

Post a Comment