# Making Things Work: Discovering How to Power The 10,000 Year Clock Sustainably

In the previous two posts “Engineering and Design for the Future: The Making of the 10,000 Year Clock Project” and “Materials and Structure that Last: The Science Behind Building a Project That Survives 10,000 Years“on the 10,000 Year Clock Project I have discussed the challenges with design and materials. A third hardship the team faced was powering The Clock. As stated previously, the design of this clock is all mechanical with no electrical components but the engineers still needed to figure out a way to both harvest and then store energy to power it.

My immediate reaction was that they would use solar power- but then I remembered the clock is inside of a mountain… Taylor told me about a workaround. “We’re using solar power, but there’s a mechanical means of capturing the energy. We have a tank on top of the mountain which heats up during the day. As the heated air inside expands, it pushes a piston, which powers The Clock.  The Clock also stores enough energy in an enormous weight to power the clock for 200 years without any solar power just in case the sun were ever blocked for some reason.”

See how the Sapphire window heats a chamber of air which in turn moves a graphite cylinder, creating a winding force needed for the pendulum

In addition to using solar power, the Clock is synchronized with the sun via a sapphire prism. The prism is placed on the top of the mountain, and at solar noon every day, the prism reflects the sunlight down into the clock and heats up a pressure chamber.  This allows The Clock to stay “on track”. When experimenting with these types of ideas it was crucial to be able to evaluate the design beforehand especially considering the size of the project and the size of the manufacturing bill. This allows them to commit to a design and stick with it, knowing they have it right through data and models.

Finding the area of visible sun in PTC Mathcad Prime 2.0

Luke walked me through the challenge of figuring how to get the 9ft pendulum just right so that it would not only keep accurate time, but also swing more slowly so it would decrease the wear over 10,000 years. He explained how he had to use a middle pivot with a 10 second swing, with the center of gravity just below the pivot. If they hadn’t gotten that one component right the entire project could’ve been thrown off.

For the Long Now engineering team PTC Mathcad and PTC Creo are time savers. The power of the programming allowed for them to accomplish complex symbolic math and graphing using lots of data. Taylor explained, “the graphing is great and really slick. There’s no compiling involved. Mathcad is very useful for calculations  – it lets you solve equations and update worksheets in real time.”

Zoe added, “I like the linearity of Mathcad. You can define a variable in one place and it changes throughout the whole document. It’s easy to read and easy to use. It probably cuts the time I spend on a set of calculations in half and allows me to spend less time double checking my work.”

If you would like to try PTC Mathcad for free to get a better understanding of how you can save time on engineering calculations try PTC Mathcad Express, a fully functional version for 30 days, and accessible for life after that.

A big thank you and good luck to the Long Now Foundation and to the 10,000 year clock team!

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