Reply With Quoteno entiendo
I don't understand dear.
no entiendo
I don't understand dear.
What are you on about ????
la palabra "dear" no esta bien en ingles (cuando se habla a un extranjero). Esta una palabra intimate, usada por ejemplo entre de un hombre y su novia o esposa.Originally Posted by cannedheat
El post estaba simplamente por mostrar una tecnica nueva para reganar la energia loque esta "wasted" (basurada?) cuando un carro se halta por el manejista. No mas, no menos.
con saludos de amistad,
I used to get drawing submittals back from a Canadian gas company and their reviewer was quite liberal with multiple exclamation and question marks. Instead of a simple "please include 3 spare analog inputs" it would be like "ANALOG INPUTS MISSING!!!!!????!!".
Anyway, the link should have been to a company which has discovered how to recover energy by helping vehicles to come to a halt. The equipment is buried in the road, not attached to the vehicle. Of interest to some, I would have thought, but apparently not so on this forum. So I've done the right thing 8)
Yes, you are right, I have misused the word dear here ( no offense intended ). This "false friends" words are still tricky to me lol.
Regarding what you are talking about, the principle is not new. Energy is already recovered in some cars, but as far as I know , at the moment this energy is only intended for the use of the car. I believe this technology comes from a gadget invented for Formula 1 cars, which recovered kinetic energy when braking and used it to boost the car when accelerating.
The idea of massively recovering it, and, putting it on the main network seems a good idea. The energy wasted from braking a 1000 kg car from 90 km/h ( highway speed ) to 50 km/h ( remote-pay toll booth passing speed, most energy rendering situation, biggest Sf^2-Si^2 ) is 216172.8 jules. That makes 0.060048 Kwatt*hour, let´s say 0.06 Kw.h. Considering an effectiveness on the retrieval of braking energy of a 90% ( neither conservative, nor too optimistic ) that makes 0.054 Kw.h.
Considering also an induction system of passing the energy wirelessly from the car to the reception system by means of two coils ( one in the car, another under the pavement: a same principle-using system is being introduced for charging cell phones ), which must convert it to altern currency (AC) to adjust its voltage and frequency to that of the main network (50 ~60 Hz ), we could consider an overall efficiency of this stage of 80 % ( quite optimistic ). That makes 0.0432 Kw.h available to be put on the network per car. An standard not very big house uses 4.5 Kw.h maximum input in Europe. That makes 104 cars passing through a toll booth for a standard house.
Considering it in the flesh, to me, some questions arise:
- No possibility of accumulation of energy. In terms of great quantities of energy, only hydraulic energy is capable of accumulating it for a later use ( batteries would be anti economic ). This means no capability of choosing when to pour this energy to the network, in order to be paid the highest amount per Kw.h at peak consumption hours ( and then is when people are not on their cars braking, but in their homes ). This problem could be solved via subsidies. Here, any energy produced by means of a renewable energy is always paid at highest rate, whenever it is produced.
- Investing on the necessary infrastructure. There is an evident difficulty on making all cars able to render this energy. This is a major problem, and with an expensive solution. Individuals won't be eager to pay more for their cars to give someone else a profit. Conversely, energy recovering systems will be an standard in a near future ( Bmw already have it as an standard ), so the most expensive part of this gadget would already exist in the car. Only the energy-transferring coil system ( which should be comparatively inexpensive ) would need to be added. That leaves us only with the necessity of energy receiving infrastructure.
So, if I would think about investing in this project, things I would ask/think are needed would be:
- Accurate traffic studies, taking into consideration multiplying factors, which could show an accurate estimation of the possible rendered energy. This is expensive and time consuming, but feasible.
- Remote energy-transferring system implementation. This is the biggest difficulty, and can turn the project useless.
- Internal Return Rate of the project, considering different scenarios, those with subsidies, and those without them. Prospected official policies on this could help.
As a final conclusion, my opinion is that this braking recovering systems have a greater future reusing the energy for the mean of transportation which has generated them, but that's just my opinion.
Just my thoughts, I am sure most of this has been thought by you, but i enjoyed putting it into writting, just as a little intelectual exercise. From my humble point of view, renewable energies, at this very moment, are only profitable via a subsidies policy, but in a free market ( which is not the case of energy, at least in Europe yet ), they can't compete ( only hydraulic energy is efficient enough to compete on this scenario )
Regards.
That is probably the silliest thing I have heard of in a while.
While regenerative brakes are useful in hybrid cars, where the existing drive motors becomes a generator durning braking and supplies electricity directly to the car's batteries, the use of regenerative brakes on a conventional automobile to power static structure would be rather wastful in the long run, with the electricity storage in the car and the extra generators and associated equipment adding weight and reducing the car's existing gas-mileage. It would be less wastful to just dump the electricity back into the car's battery and reduce the power lost from the engine to drive the car's altenator.
Although, more could be accomplished by increasing the car's internal combustion engine's efficiency from the 20% to 30% it currently is, to about 35%, thus reducing the fuel consumption, than trying to harvest the energy lost to braking. It is about like worrying about the leaks in the Hoover Dam, when a spillway is stuck open...
No offense taken. The calculation was interesting. I was surprised at how little energy resulted from the speed reduction in your example. In fact, I made it much less than 216172.8J because a vehicle weighing 1000kg (1000N) has a mass of 1000/9.81, no? Also, much of the vehicle content is non-conductive, for example, plastic, leather, flesh, etc which I assume has no recoverable energy in their system. So it could be as little as maybe 0.002 kW-h which hardly seems worth it.
What about the wattage, I wonder? Ignoring inefficiencies, if the deceleration was, say, 2m/sec/sec then it would take 5.55 sec to go from 90 km/h to 50 km/h which would be about 22000J/5.55s = about 4kJ/s = 4 kW - quite a lot of power. So maybe their system does have some merit, given a steady stream of vehicles?
Gentlemen, as far as I could tell from the link, no additional equipment is required in the vehicle itself.
Let's try to put it all together.
- Our car has a mass of 1.000 kg. Then it weighs its mass multiplied by gravity g=9.81m/s^2: that makes 9.810 Newtons ( kg*m/s^2)
- Kinetic energy does not depend on g ( earth's acceleration constant ), but just on mass ( and speed of course: that's why it is kinetic ).
- Not-conductive elements can, and in fact have, an effect on kinetic energy, which only relies on their mass and their speed. Their conductive properties are not relevant to our case. Different matters are energy transfering mechanisms - means.
- My calculus is correct. Not very accurate, but dimensionaly is correct, and, whatsmore, optimistic. xpatUSA, may I say you are mistaking power with energy on your calculations.
- MUCH further equipment is needed on the vehicle. But part of it is becoming common.
- This idea ( recovering energy from braking ) is not new. F1 cars and trains are already using it. Also the ubergods-engineers of BMW are already using it as a standar on their ( fabulous ) cars, with great results (see efficient dynamics from BMW ). Take a look at that lysanderxiii ( well and GM too :twisted: )
- lysanderxiii, efficiency on termic engines has been sought during the last century, with major pushes after wwi, after wwii, and especially during the three decades after 70's energy crisis. Little can be done about the small efficiency numbers ( 30 % ) of internal combustion engines ( although I hope it's done, sometime ). Investment on this thing is probably a silly idea. Going to the moon was too. But its principle is not.
- Investing on this kind of business, in my opinion, is just very risky, even reckless. I do not find their info at their web page neither reliable, nor true, and whatsmore, tricky. Energy investment is a good idea for medium term purposes, but nobody will give you bucks at cent's price. My 2 cents are nuclear, gas, and hydraulic ( which is almost exhausted, in terms of available locations), with different considerations regarding terms of investing fulfilment.
regards, and thanks you two for sharing your opinions with me. lets keep sharing thoughts please.
cannedheat
gracias, pero no. All we are doing is misunderstanding each other.
No you may not, thank you.
after 50 years as an Aircraft technician, then a Gas Turbine design engineer and finally an Electrical and Instrumentation Consultant at Rolls-Royce - I don't need to hear that I do not know the difference between energy and power. Sorry.
con saludos cordiales,
Wow, that's impressive.Which sector do you work in ? civil, militar ? Then you are sure aware that you mistook weight with mass ( which is something very common with this plethora of units that we can handle ). I am also sure it must have been due to a unit converting problem ( I am not sure, but, do you work imperial or metric ? I guess imperial sistem: unit systems are always a headache! ) As engineers, we must be aware, that mistakes will be made. Anyone who says he never makes mistakes will be either lying, or he never tryed to do anything. The really important thing is solving those mistakes as soon as possible, and with great eagerness.
I would like also like to point out that the aforementioned mistake of power and energy is thought in terms of power needed to brake the car and energy put on the electric network, and its power, those are the concepts I believe you were mistaking, not the general concepts power and energy, which dimensionally you have handled correctly.
I must apologise for not stating that on my previous post.
Power needed to brake the car, Pb. This power would have nothing to do with the power of our electric network in the case of different braking-retrieving and network-yielding systems, which seems to be the standard for these kind of devices in cars ). The power yielded to the electric network will depend on the energy retrieved per car, and the number of cars that yield that energy during certain time ( power = energy/time ). But the power needed to brake the car is something that would only inffluence the car braking energy retrieving system. Also I would like to say that when the car brakes, it retrieves the kinetic energy of everything inside the car, as everything inside it decelerates ( its not metallic components too ).
Anyway, I really enjoy sharing thoughts with senior engineers. As a professional chartered ingeniero de caminos, canales y puertos, ( not at all equivalent to american civil eng.: more similar to french ponts et chaussées ), I believe that this conversations enrich myself, and hope they enrich others too. It is a great pleasure to make the mind work a little bit, and share different approaches on different matters. I have found this subject very interesting. I usually gather with a friend of mine, who is also a retired senior telecomunication engineer in his 60s, and we do enjoy long conversations about technical things, sometimes enjoying a good bottle of spanish red wine.
Finally, let me deeply thank you and all the elder engineers that have worked before us, the younger ones. We are here thanks to you, and we will try our best to keep on with all this.
Best regards.
PS. please forgive my poor english
TOUCH DOWN! :thumbright: :thumbright: :thumbright: :thumbright:gracias, pero no. All we are doing is misunderstanding each other.
No you may not, thank you.
after 50 years as an Aircraft technician, then a Gas Turbine design engineer and finally an Electrical and Instrumentation Consultant at Rolls-Royce - I don't need to hear that I do not know the difference between energy and power. Sorry.
con saludos cordiales,
I'm not as think as you drunk I am.
Until you read cannedheat's reply.
I wish I understood the physics involved.
We, as ingenieros de caminos, are at the service of the people. Over any psychological matters.
Engineering is the core of being human, whatever artists may say.
The world can be handled in a better way.
Yours,
canned_heat
I must say, both of these statements have a great deal of merit whatever the math says.Engineering is the core of being human, whatever artists may say.
The world can be handled in a better way.
Engineering may be the core; art is its soul. ;)
engineering has a very strong artistic and creative component in it ( not as science, which doesn't )
maybe engineering is some kind of art, or art is some form of emotional engineering.
anyhow, I like both art, and enginering.
regards
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