Fireplace Fan Motor Experiments
In a recent blog post I wrote about some of the challenges that have come up in the process of developing new prototypes for energy harvesting exhibits. Despite the frustrations, I’m excited to keep exploring new materials and ideas for this project.
Recently I tried some more experiments with peltier elements which are really interesting materials that can generate heat or cooling when supplied with electricity An interesting property of these parts is that they can also be used as generators when hooked up the other way to make electricity to power lights or motors when one side is much hotter or cooler than the other. They are sometimes used in this arrangement for fireplace fans which use the hear of the flames to power a fan to blow the air through the chimney. I ordered a fireplace fan kit on amazon (it was about 20 euro although I saw them for cheaper on ebay) and started to experiment.
The first experiment I tried with a candle giving direct heat in the normal way that this part would be used. And sure enough it quickly generated enough electricity to power the motor (and it even kept spinning a bit longer after blowing out the candle). While a really nice demonstration of the effect it’s not so practical for the museum setting as an open flame is not the best idea for the exhibit hall.
As another test I experimented with using a hair dryer to heat up one side of the peltier element. This did eventually work but the motor needed a bit of a twist to “jump start” the spinning. It’s a bit more practical to use hot air and one next step that I want to try is a heat gun used for soldering and heat shrink tubing application as that gets hotter and more direct than a hair dryer.
I would still like to figure out applications for this element that use heat that would be generated anyways and otherwise lost into the environment. Running a hairdryer off wall power to trigger the motor doesn’t yet scream energy harvesting to me but at least it’s a step in the right direction. Along with my colleagues at the Phaeno Science Center in Wolfsburg, I’ll keep experimenting with these ideas and share the results here on the blog!