Jack, I am afraid there are some issues with your reasoning on this subject:
I am from The Netherlands and am very well aware of frozen roads being cleared from traffic driving over it. Just tell me - is that clearing from the vehicle wheels pushing the snow/ice around, creating heat or from the hot car underside radiating heat or from the hot combustion gasses that are left behind after the car or from the warm tires that are known to heat up from continuous flexing due to repeated striking the road surface? In addition - in The Netherlands it is common that on busier roads, the municipalities will distribute road salt, so that they can speed up the thawing of the snow/ice on the roads, which is why busier roads are clean much sooner than the roads that have not received the salt. It is possible that a road warms up from flexing, but the flexing of concrete is so minuscule, being a brittle substance, the flexing *has* to be miniscule or it will crack! So I doubt that it has any significance for concrete. Asphalt and other softer substances, I can see flexing and absorbing energy, part of which you can capture. When energy is captured from flexing, then the flexing *must* change, you cannot have the identical flexing in the road as that would violate the law of conservation of energy - unless no energy is produced. So, if electric energy is removed from the road, it has to originate somewhere. Either from the road flexing differently (less) or from the cars expending a little more energy - it has to come from somewhere. Concrete does not need steel to stop it from flexing. In fact, (as you indicated yourself) the steel will flex plenty when beams are laid down, after which the concrete is poured around them and the flexing becomes very little (it has to). The reason that there is steel in concrete is to mitigate the one weakness of concrete: it is brittle and if you try to flex it too much, it will crack. Essentially the concrete is perfect for loading (pushing) on it and it will almost not flex because it is rock hard, but you cannot pull on concrete, it will easily crack and pull apart. So that is why there is steel in concrete, to allow pulling forces to act on the steel and keep the concrete in one piece. If the pulling forces can be very large, then one of the tricks that is often used in bridge building is to "pre-load" the steel reinforcement. This can take different forms, a common one is that the concrete is not poured with the steel in place, but the concrete is poured around hollow tubes. After drying, the steel reinforcement is pulled through the tubes, a screw tread is cut on one or both ends of the steel rods and using nuts, the steel is tightened to provide a compression force on the concrete that is larger than the largest external pulling force that can occur in the application it is in, so that the concrete at all times will be under compression, no matter if the external forces are pushing or pulling on the concrete. I am well aware of ways to measure mechanical strain / flex on components by adding "strain gauges" on them, measuring the distortion similarly to what a piezo element can do but those gauges do not generate energy, they create either a resistance difference or can create a voltage that is measured with a high impedance instrument, so the measurement does not affect the test. In the case of road embedded piezo elements, you need to change the "test" in order to harvest energy, so you are tapping energy from the component, so it has to influence its environment to harvest that energy. The question is how much can be harvested and from where does that energy come. I am quite sure that more than 99% of that energy will come from the cars traveling that road experiencing a higher loss, especially when we are talking about a concrete freeway surface. I agree that there are different ways of embedding or adding piezo elements to the road, the question is if it makes any (economical) sense to go through the cost and how much power will be generated, does it even pay back? Then the question if this increases the losses of the cars passing by, this effectively means that you are levying a "toll" that is paid by the passing cars in their increased fuel use and increased emissions. Do you want that? I think there are still a lot of questions to be answered before this could be considered for mainstream use, some of which are ethical, some technical. Cor van de Water Chief Scientist Proxim Wireless office +1 408 383 7626 Skype: cor_van_de_water XoIP +31 87 784 1130 private: cvandewater.info http://www.proxim.com This email message (including any attachments) contains confidential and proprietary information of Proxim Wireless Corporation. If you received this message in error, please delete it and notify the sender. Any unauthorized use, disclosure, distribution, or copying of any part of this message is prohibited. ________________________________ From: Jack Wendel [mailto:[email protected]] Sent: Friday, August 26, 2016 2:17 PM To: Cor van de Water; Electric Vehicle Discussion List Subject: Re: [EVDL] Piezo-power> 10mi of freeway could charge all the EVs in Burbank-CA(?) Cor wrote: The laws of energy conservation are simple, in order to extract energy you have to take it somewhere. No matter that the road already flexes, to take additional energy you will need to either allow it to flex more That simply isn't true. The road is currently flexing and that energy is currently being wasted because it is not being captured. The correct application of this technology would simply capture the energy of the exiting road flex. In the end result, the road would neither flex more nor less. Ideally, the road would flex less and the reduction in rolling resistance would be an added benefit. Most setups with piezo elements that I have seen, do not have elements inside the surface, they are not capturing energy from the flexing of the surface, but instead they are mounted *under* the road, Our were mounted on the side of the material. The piezo element was distorted with the existing material and had no measurable impact. If you truly want to embed piezo elements in the surface of the road and want them to flex, you will probably need to make the road flex a bit more than today's costly concrete (stiff) freeway surfaces. That adds losses to the movement, just like riding on sand takes more energy While people tend to think of concrete as stiff, it still flexes due to weight. If it didn't they wouldn't add steel to reinforce it. If concrete didn't flex there would be no advantage to adding steel. Just recently I was driving down the highway and saw huge concrete road beams being transported. The cast shape of these was in a gentle arc. That arc goes away when the road is build due to the loads. It takes a LOT of energy to flex those beams to be straight! And there's no 'sinking into' those beams. but it will sure remove energy from the vehicles passing (lower MPG) in order to generate power, Cor, I completely understand what you are saying but your approach is only one of many possible ways to implement this technology. It also represents one of the worst ways, as you clearly point out. there is no free lunch It's not free, it's simply recovering energy that is currently wasted because it is not being recovered. unless you are able to design a road in such a way that you can reduce the losses in the road itself and "steal" power from the road, rather than from the cars. But due to the fact that roads do not seem to heat up a lot from traffic, there is probably more much loss in the road that you can capture. I am confused how anyone cannot be aware that roads heat up due to traffic. Here in Dallas Texas we have days that are just below freezing. On those days, the well traveled roads are clear because the precipitation melts. The less traveled roads stay frozen until the temperature rises or more traffic travels on them. This is a clear indication that roads heat up due to traffic. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20160826/42172503/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
