Does anyone have any data regarding the amount of waste heat that the vehicles produce?
Since when is dispelling excess heat a waste?
I was just interested to know where the best place to deploy a novel thermoelectric power generator might be on an electric vehicle....
Well, the only physical place that heat is expelled is in the front wheel wells, when the fans come on to cool the battery pack, or more specific the coolant. Using the MS as the example, in addition to the fixed open grill in the middle of the nose, in the lower right and left corners there are temperature controlled flaps. When the battery pack coolant gets to a certain temperature, these flap open and fans come on to draw air through them, expelling it out through the wheel wells. I can tell you it is hot.
This routinely happens in the summer time when one is charging, because charging creates additional heat.
The AC motor creates heat as well, but that is captured by the coolant. So the front end is where everything gets expelled.
And the brakes on the rare occasions when you use them.
thats great thank you! Do you know the rough size of the flaps?
You realize that the coolant temp is tepid at best. The power available will be tiny. Electric power to motive force is very efficient- very little waste heat.
@willjohnburton - do you plan on using the recovered power to charge the battery, because that's treading on perpetual motion property, which is unlawful in the physics sense. (Goes against the laws of Physics)
we do not plan to do anything at the moment UnshodBob we are just investigating. I will make sure to remind the Cambridge University Professor working on the project with us about perpetual motion - I would not want him to fall into that trap... now back to my nuclear fusion reactor.....
You mean FocusFusion?
UnshodBob; Recovering energy that is 'wasted' as heat would not be perpetual motion. However it is probably impractical.
@wj - I said it is treading on PM property, meaning it is a slippery slope to PM. didn't realize the OP was a nuclear physicist at Columbia University. Just sounded like another PM wannabe to me. Now I have to get back to my miracle cancer cure work...
Closely related to OP's idea, I was thinking it would be really cool to invent a solar powered lamp. Any comments on this?
UnshodBob we have solar powered lamps already. Aka 'a window.'
best solar powered lamp i can think of is the Sun?
It was a joke. Why would a supposed nuclear fusion guy want to capture "waste" heat using a "novel thermoelectric power generator" on a vehicle with a 60 kWh-90 kWh battery? Why not just tap into any 12 volt wire and use that? It makes as much sense as a solar powered lamp. Get it? :)
P.S. - I'm not working on a cancer cure, same as OP isn't working on fusion reactors.
Now i get it... good one
Thermoelectric systems, if they can be scaled up using novel materials rather than the current 1st and 2nd generation materials, MAY offer a way to convert waste heat into power. That power can then be channeled to the batteries and give extended range to vehicles. Its not really hard to understand.
The theory of thermoelectrics has been around since 1821 and its discover by Thomas Johann Seebeck. The Russians invented a kerosene lamp that would power a radio and more recently Biolite have camping stoves that charge mobile phones.
All these devices share one common factor which is efficiency, or lack thereof. However there are potentially other materials that may for various reasons offer a solution to this issue. BMW are researching in this area as are other car manufacturers, as are we....
Caveat: I'm not an engineer or expert except when typing on the internet. :)
BMW and other manufactures have been looking a ways to recover some of the lost energy of heat. However this is from an ICE. In an ICE about 75% of all the energy in a gallon (or liter) of fuel is wasted as heat. Also in an ICE you have a centralized system for recovering a large percentage of this heat.
In an EV the amount energy wasted as heat is obviously a LOT smaller and probably (guesstimate) in the >20% range. Also unlike an ICE there is no method in place for gathering this heat. For instance the motors are air cooled (I believe).
So adding systems to gather and convert this small amount of wasted energy would probably be prohibitory complex and expensive for a small return plus it would add weight (the last thing an EV needs).
EDIT: Should be <20%
@wj - So, waste heat from a battery running a motor goes through your device and back into the battery to run the motor? Doesn't sound like perpetual motion to me at all. (not)
UnshodBob: No because any heat released is not energy that is accelerating the car or used in any way (other than heating). Any heat the motor gives off is wasted and is not energy used in moving the car. If you capture this wasted energy that was NOT used then you could increases the efficiency. It is not perpetual to try and reduce what you waste and increases efficiency of what you have.
HOWEVER I don't believe there is enough wasted heat/energy in a EV to make it worth the efforts to recover.
Here is another way too look at it. You have machine that takes 80 units of energy to run for 1 hour and is 80% efficient. You have 100 units to run the machine. It will run for 1 hour of of the 100 units., using 80 units and waisting 20 units to heat. Now if you can recover 10 of the 20 wasted units and put back into the system the machine will now run for 1 hour and 5 minutes (you will still lose 20% of the 10 units you put back in) off the same 100 units of energy.
There is nothing perpetual about utilizing more of the energy available to preform the task at hand.
Again I don’t believe this is practical and I’m not proposing it should be done. Just that it is NOT perpetual.
Ok. You are treading the border as I said before, but only flirting with PM. There is a process called "combined cycle" for electricity generation that uses gas turbine generators to create "peak" power during summer months in Socal and the hot exhaust from two jet turbine engines is run through a single heat exchanger to create steam for a conventional steam turbine-generator as is used at natural gas, oil or nuclear power plants. That process captures a large amount of waste heat and is profitable, as far as I know. I worked at Southern California Edison until 1990 and we were using that process then. I agree with you that the amount of waste heat available from the Tesla is not worth worrying about. I'll just enjoy the neck-snapping performance. :)
Wj is correct. He is saying total efficiency could be slightly higher.... not a net positive pepetuum mobile.
He is also correct that an ev wastes so little to heat that it isnt worth it.
However the battery and motor share a liquid cooling system and there is a heat exchanger to ambient; howeve the temperature is below 100F unlike an ICE, so the recovery opportunity (temperarure relative to ambient) is modest.
Consider radioisotope thermal generators. The radioisotopes put out 1500W of heat for 100W electricity recovery.
Here is one that always totally amazed me. A friend had a camper on his pickup truck that we took out to the desert. When we got set up, he went to light the propane refrigerator. He had to start a fire to make the refrigerator get cold inside. That totally blew my mind. It is so counter-intuitive that I was and still am amazed at the power of engineering.
Now Tesla is doing it again. When I press the go pedal, (not the go peddle @Go_Peddle_4_me,) I am still amazed by it. Most modern devices would appear to be magic to earlier civilizations. The iPhone I am typing on, the Tesla, the propane refrigerator, television, dynamite, and the wheel - oh, yeah, the hydrogen bomb would count, too. All appear as magical/terrifying things to people from prior eras.
I looked up who invented the propane powered refrigerator and the first link was for the Einstein refrigerator. Yes, that Einstein. Albert! Of course it blew my mind. The year was 1926. No moving parts. They say it is making a comeback. Very green. No freon. It uses ammonia. Maybe same as the one Harrison Ford built in The Mosquito Coast.
There is NO gray area in perpetual motion. Nothing I stated has any relation to perpetual motion in any way. Also keep in mind you can recycle energy that has already been used to run a machine and this is NOT perpetual either. All (or almost all) EV's including Tesla do this with regenerative braking. :)
DTsea, thanks for the correction that the motor(s) is/are liquid cooled.
You are welcome wj. I enjoy reading your lucid and interesting posts.
Battery heater is resistive I believe as is the cabin heater. There is probably a more efficient way to do both those tasks. Battery cooler uses a compressor and refrigerant so probably has a c.o.p. of more than unity.
@wj - I concede that you are not proposing a perpetual motion machine. Ok? I never said you were. I saw a path you were on and in my mind, the direction of that path "headed" towards perpetual motion territory, and I thought I was clear saying it borders on or you are flirting with PM. it was walking like a duck and I expected it to quack like a duck. It didn't quack, but I expected it to. I was having a little fun, too. The solar powered lamp was funny to me. The loop of battery/motor/waste heat/device/battery/motor isn't much different from battery/motor/kinetic energy/regen/battery/motor except in scale. People may have scoffed at Einstein's refrigerator, too. Don't take it personally. It was meant not as a personal attack, but as a caution not to enter PM territory. Peace. :)