crossbreak
1 MW
yep, but even a 2stroke can have this efficiency... ok not in this package and at this noise level.
Hydrogen fuel cell range extender EBIKE
- Thread starter speedmd
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speedmd
10 MW
Some more on the magnesium air cell. Claim 7.5 times more effective than li ion batteries.
http://magnesiuminvestingnews.com/6...en-united-states-military-japan-magpower.html
http://magnesiuminvestingnews.com/6...en-united-states-military-japan-magpower.html
liveforphysics
100 TW
Its like a bad joke that people keep funding.
If you use CO2 as your carbon source, you have to input the carbon combustion energy to separate the O2, which means you can only have a net loss of energy. If you start from water to make H2 you simply waste ~30-40% of the electricity in electrolysis losses, if you start from cracking natural gas for H2 you just wasted half the energy available in stripping that carbon.
Then once you've got a tank of H2, it once again wastes 30-40% of that energy as heat when you try to make electricity with it. Its like the only tech with enough series losses to ultimately use electricity to drive the wheels, yet carries greater total system inefficiency than ICE's done well.
No matter how you look at it, going from electricity to H2 or CNG to H2, you have less total inefficiency in the entire battery EV system (charger/batts/controller/motor) than simply generating the H2, and then the fuel cell wastes another 40% of that energy anyways.
I have a number of friends who are off the grid entirely with solar charged EVs as there only transportation. Many more with solar on grid tied inverters and EVs who are net energy producers for the grid AND handle all transportation energy.
That makes it a solution. Where are you going to add H2 PEMs into that sustainable working system and do anything more than waste a bunch if energy pointlessly?
If you use CO2 as your carbon source, you have to input the carbon combustion energy to separate the O2, which means you can only have a net loss of energy. If you start from water to make H2 you simply waste ~30-40% of the electricity in electrolysis losses, if you start from cracking natural gas for H2 you just wasted half the energy available in stripping that carbon.
Then once you've got a tank of H2, it once again wastes 30-40% of that energy as heat when you try to make electricity with it. Its like the only tech with enough series losses to ultimately use electricity to drive the wheels, yet carries greater total system inefficiency than ICE's done well.
No matter how you look at it, going from electricity to H2 or CNG to H2, you have less total inefficiency in the entire battery EV system (charger/batts/controller/motor) than simply generating the H2, and then the fuel cell wastes another 40% of that energy anyways.
I have a number of friends who are off the grid entirely with solar charged EVs as there only transportation. Many more with solar on grid tied inverters and EVs who are net energy producers for the grid AND handle all transportation energy.
That makes it a solution. Where are you going to add H2 PEMs into that sustainable working system and do anything more than waste a bunch if energy pointlessly?
Sounds like if you have natural gas to hand it's better just to burn it in an ICE?
Using electricity to greate the fuel for the fuel cell sounds like an attempt at curing the problem of energy storage with EVs (low energy density and long recharge times of batteries). Perhaps this was a good idea 20 years ago and people started messing with fuel cells, but it looks like battery technology is advancing enough to make it a moot point?
It seems that today's batteries are (just about) energy dense enough and can be recharged quickly enough, they're just too expensive. Fuel cells costing orders of magnitudes more sure doesn't sound like the answer that problem.
Using electricity to greate the fuel for the fuel cell sounds like an attempt at curing the problem of energy storage with EVs (low energy density and long recharge times of batteries). Perhaps this was a good idea 20 years ago and people started messing with fuel cells, but it looks like battery technology is advancing enough to make it a moot point?
It seems that today's batteries are (just about) energy dense enough and can be recharged quickly enough, they're just too expensive. Fuel cells costing orders of magnitudes more sure doesn't sound like the answer that problem.
crossbreak
1 MW
liveforphysics said:
this value is a bit theoretical. The real world efficiency is even below 60%.. if you wanna get some power within a certain package it will be even lower - I guess. you still have add the loss of the electric motor, another 10-30%. engines get up to 40% real world efficiency with CNG, up to 37% with gasoline. Example: the GM Volt engine sucks around 235g /kWh. A consumption of 83g/kWh would mean 100% efficiency, so the Volt gets around 35%. I'd really like to see some real world figures like these about fuel cells.
more efficient, but loader and more pollutant
speedmd
10 MW
Idle, full load or average? What about transmission/ differential losses. Not seen any data suggesting ICE run as efficiently as 40% other than super high compression ratio direct injected turbo diesels going by the makers claims. Most ICE drive systems currently in use most likely run 25% at best.
crossbreak
1 MW
?What do you wanna know exactly?? "100% efficiency" simply means there is 1kWh of energy in 83g of gasoline
if you live in the US, the 25% may be the average. "Super high compression ratio diesel engines" get around 50% efficiency, they are use in ships. Supercharged car diesels have rather low compression ratios, 40% efficiency is nothing special for a car diesel.
http://en.wikipedia.org/wiki/Internal_combustion_engine#Energy_efficiency
That figures with the best diesel engines reaching circa-40%. IIRC diesel engines are theoretically about 10% more efficient than petrol equivalents (mostly down the higher compression ratio AFAIK). Real-world mpg figures exagerate this due to the higher calorific content of diesel and its density (considering you buy and measure it by volume, not by weight).
IIRC the enourmous diesel container ship engines operate at up to 50%.
crossbreak
1 MW
79.4g diesel fuel contains 1kWh . The car diesels that are made from cast iron can get 198g/kwh. that is 40%. i agree, this number wasn't increased since a decade. The 18-20% is a figure that is made up out of thin air. The source is some educational homepage, not a serious paper. Maybe true for the US that has an overaged car fleet. Definitely not for all parts of the world
Anyway, a quite interesting "take away" electricity source are mechanically rechargeable Zink Air batteries. Sadly they are not very common.
Anyway, a quite interesting "take away" electricity source are mechanically rechargeable Zink Air batteries. Sadly they are not very common.
I assumed the 18-20% average efficiency represented "normal" use. I.e. 40% peak efficiency, 0% when idling, and everything inbetween.
Whether deisel engine efficiency has increased much in the past decade (introduction of common-rail injection, I'd assume) is a good question. They've certainly been getting more powerful.
Whether deisel engine efficiency has increased much in the past decade (introduction of common-rail injection, I'd assume) is a good question. They've certainly been getting more powerful.
speedmd
10 MW
These ICE numbers are at the crank* and at full load. Who runs them that way other than the ship captain. Real world, tank to tire numbers are not close to this and run in the 15- 20% range on most of the fleet. Remember the sources of much of this research is paid for by the folks that make their living making ice vehicles. Agree we drive tanks in the US. Most of the tiny high compression turbo diesels are not for sale here. Folks are too busy running around in 7000 pound super duty pickups with dual 6 inch stacks to worry about getting fuel economy.
liveforphysics, you also didn't mention compression losses. You lose power when compressing hydrogen or CNG into a tank; to get the gas dense enough that you could actually get a good amount of energy out of that tank.
That is yet another loss in the whole scheme. You also have some amount of leakage.
There is no current way to create hydrogen and use it with anything other than laughable efficiency loss and poor economics across every single stage.
It sounds cool that you could run your car on an emissions-free fuel that is elementally very simple and does not have the long refueling times of a battery, but you are still beholden to technical and economic factors
That is yet another loss in the whole scheme. You also have some amount of leakage.
There is no current way to create hydrogen and use it with anything other than laughable efficiency loss and poor economics across every single stage.
It sounds cool that you could run your car on an emissions-free fuel that is elementally very simple and does not have the long refueling times of a battery, but you are still beholden to technical and economic factors
speedmd
10 MW
I understand several sources are claiming they are now using pem electrolyser systems that are tub to tank 70% efficient. You can Refill in seconds. Cost is a bit high.
AFAIK, they range from 40-60% from what i've heard.
You can also run them on natural gas. That seems like the way to go for best carbon efficiency, rather than losing all kinds of power converting it to hydrogen.
Yes, it will pollute at the source instead, but not much. Far less than something like an internal combustion engine would running NGV through the injectors.
That is one application where i could see fuel cells doing an awesome job. If we are going to use fossil fuels, let's do it in the most efficient way possible.
I'd run a natural gas fuel cell any day because i know it would be providing much cleaner power overall than what i would get from my power plant.
You can also run them on natural gas. That seems like the way to go for best carbon efficiency, rather than losing all kinds of power converting it to hydrogen.
Yes, it will pollute at the source instead, but not much. Far less than something like an internal combustion engine would running NGV through the injectors.
That is one application where i could see fuel cells doing an awesome job. If we are going to use fossil fuels, let's do it in the most efficient way possible.
I'd run a natural gas fuel cell any day because i know it would be providing much cleaner power overall than what i would get from my power plant.
liveforphysics
100 TW
I agree the natural gas direct system would be less waste/polution. However, in a world with proven capabilities to have cleaner than a coal plant shouldn't be a prized objective IMHO.
speedmd
10 MW
Direct methane fueled cells have some huge benefits dealing with compost gas. Deals well with land fill methane also. Locally there was a state push for a high temperature turbine to run off the plants sewer digester gases.
speedmd
10 MW
Hyundai announced today the time frame for the Tucson. First to hit the street in a production H2 car. "Hyundai tells Tucson fuel cell story"
http://www.dispatchb2b.com/TheNewsl...alls-it-next-generation-electric-vehicle.aspx
http://www.dispatchb2b.com/TheNewsl...alls-it-next-generation-electric-vehicle.aspx
docnjoj
1 GW
A number of cars these days (not just the Prius) shut off the engine at a stop instead of "idle" which in city traffic really helps efficiency and reduces pollution. More to come, I hope.
otherDoc
Subsa
1 mW
- Joined
- Dec 30, 2013
- Messages
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Fuel cell now, looks like the electric car, before 20 years.
I think will be problem with so many water on the road in the winter.... ice, you know.
This type of cell, which most selelrs offer is bad choise, because is not rechargable at home.
Is matter of time someone in this forum or in his job to make mass production bicycle cell.
To reverse the process using the same hardware is the best thing, that can be done.
I think will be problem with so many water on the road in the winter.... ice, you know.
This type of cell, which most selelrs offer is bad choise, because is not rechargable at home.
Is matter of time someone in this forum or in his job to make mass production bicycle cell.
To reverse the process using the same hardware is the best thing, that can be done.
rich43
10 W
I am struggling to see the point now I have a 1000w charger, plus they are difficult to refill and there's no refilling infrastructure. I can charge 4 6s lipo's in 30 minutes. I can carry the charger around in my cargo trailer too. Quick enough for most people. Better off just filling the space occupied by the hydrogen stuff with more batteries. I also hear the fuel cells degrade just like batteries.
Once I have 15ah 24s lipo, I will have plenty of range anyway
Once I have 15ah 24s lipo, I will have plenty of range anyway
speedmd
10 MW
No doubt, no infrastucture for the h2. Heavy and expensive also at this time. At some point you will cross paths and see that the stored fuel and on board generation is more power dense than the current battey technology, but not now or on a ebike and certainly you are most likely better off with a few more bricks. With a car or plane you have much horizontal surface area to lay out solar cells to recharge/ use as you go. On a bike you must stop and charge, or refuel. If batteries could be charged in less than say 10 minutes, it would be a great break through. At the current range and charge times, they are certainly limited to a secondary vehicle for most folks. IMO it is best to have technology compete for the best solutions from many directions. If on board generation has a place to expand use of e drives we should all support it. Weather it is h2 storrage or some other storage / generation method we should all be receptive. Remember that just a few short years ago, electric / battery powered bikes/carts were considered as mostly kids toys or yard tools. Never something you would venture far from the grid with. It is only with the evolution of the battery (mainly from the rc push) do we have what we have now. We are certainly in interesting times. I think that some would say that is a old chinese curse. I think it is a curse mainly for the folks that are invested heavily in the status quo that this applies. An old preffesor used to say daily, "adapt or perish".
Happy new year!
Happy new year!
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