Wednesday, February 6, 2013
Electric car idea
Here's an idea for an electric car--- use a flywheel. The flywheel can be relatively small and would take the place of the battery. Let's say about a 7 kwh flywheel. If the average of 3 miles per kwh, this would give a range of 20 miles or so.
By the way, let's explain what a flywheel is. The flywheel is a device which stores energy by spinning at a high rate of speed. In order to take energy from it, reduce the speed. To put energy back in, increase speed again. The speeds can be pretty fast, maybe over 50 thousand RPM.
In addition to the flywheel, add a 20 kwh bank of Aronsson's fuel cells. There would need to be four 5 kwh fuel cells. These should fit inside the hood, or somewhere inconspicuous. It would take 20 kwh of fuel cell capacity in order to keep the vehicle at highway speed, or maximum discharge rate of a battery, or in this case, flywheel.
The fuel cells would be powered by hydrogen, which would be kept at cryolytic temperatures. The ultra-low temperature of the hydrogen could be an asset as opposed to liability. For example, add a small Stirling engine. This would take advantage of the temperature difference between the very low temperature of the hydrogen, plus the outside temperature, or the fuel cells in operation. Such a device could run all of the electrical accessories and help out with the power system in general. Furthermore, liquid hydrogen could be used for superconducting bearings which would minimize friction on the flywheel. That would make the flywheel more efficient. Finally, the low temperature of liquid hydrogen can be used for climate control ( in conjunction with these other functions).
Finally, you would add in ultra-capacitors for regenerative braking. Ultra-capacitors can take hundreds of thousands of charge/discharge cycles. They can't hold much energy, but can give a hefty boost that would come in handy during passing maneuvers and other quick acceleration scenarios.
The benefits of such an arrangement of technology? It would be best described as longevity. One problem with batteries is that they need to be replaced. If the batteries are big enough, that becomes a big job and expensive job. Contrast that with a flywheel, which is already smaller than a battery to begin with. Another advantage is compactness in weight and size. Since all of this must fit on a car, the relatively small size of these various pieces should fit on a car.
Such an arrangement of technologies takes advantage of a number of features of each which complement each other in turn and makes the proposed idea efficient and durable.