"lindseyk"
"Michael Noire"
this was an idea I came up with while noticing something odd about thermal changes. As you all know when a substance changes in temperature it's volume also changes. Normally we think about thermal energy in terms of loss - that is to say, burning fossil fuels and boiling water to turn turbines.
What I'm proposing is actually a very slow cycle.
As a planet rotates, the surface temperature changes from radiation variations of sun exposure. Like clock work, the surface experience shifts in pressure.
The temperature to expansion ratio of different substances - such as quartz, aluminum, and water, are all different. They are so different, in fact, that hydraulic systems could be constructed using them.
A giant plate of one substance sandwiched between another can form pressure. This pressure can then be transformed into electrical energy in a variety of ways, or even stored in a capacitor, supercapacitor, or flywheel.
Such a process could also be used for large rotating satellites, or even desert engineering projects on Earth.
an interesting idea. piezos operate on the principle that distorting certain non-symmetric crystalline lattice will induce a charge difference within the unit cell, and on a macroscopic level an electric field and/or voltage within the material. since the electric field is proportional to the distance between the + & - charge (and hence the displacement and therefore strain) it follows that relatively large amounts of strain are necessary to generate an appreciable amount of voltage. since most material's CTEs are on the order of 1-10 ppm/degreeC, the temperature difference in the surface of a planet will likely induce negligible amounts of strain (thus voltage) during the course of a day. to be viable as an energy source, your piezo material (say quartz) would have to be a very large & continuous material that experienced very large amounts of strain, which is probably not feasible for the situation you've described. good brainstorm, though!
1. while most materials are X, some materials are Y.
2. the pressure available is not a measure of weight per square meter, but the combined weight of all surface area and volume that changes over a large area of exposure.
Since this source of energy is free (planetary rotation/solar powered) and the pressure can be distributed via hydraulic systems over enormous areas and concentrated, the pressure attainable is several thousand times what you might imagine it to be.
It's similar to the principle of stone excavation used by ancient people in temple construction: you add water to a bunch of logs, believe it or not, they expand with such force over time as to crack monolithic stones.
