sports850 wrote:
edmands_3 wrote:
Yes, cars can run off hydrogen, it is a perfectly valid fuel. No, you cannot split it using your battery then burn it again for a net power gain. You are using your battery to split it, then using the power from burning it to power your alternator to charge the battery again. As stated earlier in this thread, you cannot gain power like this. You split the hydrogen at 95% efficiency, burn it at 95% efficiency, and charge your battery using your alternator at 95% efficiency you lose 27% of your power (0.95x0.95x0.95 = 0.729). That is a best case scenario, it is very unlikely that you would reach anything like this efficiency.
I'm just trying to get my head around the maths involved in this , not doubting your calculations but I would have thought the energy produced by burning hydrogen and oxygen in a car's engine would be greater than the energy required to seperate water into the base molecules ? Even allowing for losses in generating the electricity through magnetic force and heat loss/friction in the engine I woulkd have thought it would produce more energy . Kind of like a supercharger , it might drain 5 horsepower (hypothetical value) to run but produce an extra 20 horsepower to make a practical gain (even with using more fuel) , wouldn't the increased economy or reduced fuel intake from running an engine on hydrogen enhanced petrol be greater than the extra fuel needed by the increased drag caused by the alternator having to work harder to produce more power ?
The energy from separating the water is the same as the energy from burning it. When you break it, you are using energy to break the bonds to split the molecules apart into their components. When you burn it, you are getting the same energy back as the bonds form again and it goes back into water again. The energy value is the same in both cases, because the start and end products are the same, with the same chemical bonds.
So basically, you use a certain amount of energy from your battery to split the water, say 20 units of energy, then you burn the water from that for say 17 units of power (in the form of motion though), then you use that motion to turn the alternator and charge the battery again with say 15 units of power. So you are making a loss of 25% overall because of the frictional and heat losses. Without losses, you would end up with 20 units of energy back in your battery again. (My earlier calc just used 95% as an example, I don't really know what the efficiency of your engine or alternator would be, most likely a fair bit less than 95%)
It works essentially in the same way as a rechargable battery. You have the reaction when the chemicals react together which produces power. Then you put power back into it as you charge it again, which splits the chemicals in the battery apart again. This leaves you where you started, but you have lost some power along the way from the inefficiencies. The only difference in this case is that instead of putting the water back into the battery, you are putting it out the exhaust, so you would have to top it up periodically.
Its also worth noting that not all chemicals act in this way with the breaking of bonds using energy and reforming the bonds releasing energy. Some work in the other way, the main ones are radioactive, where the element splits and the pieces that have split hit others molecules and cause them to split, releasing energy with each split (in the form of heat). This is why radiation is used as a power source as it naturally occurs with energy that can be easily released in a controlled situation. It is also what makes it dangerous because it can continue splitting if you don't control it and release huge amounts of energy. (Fusion is the opposite, where joining two chemicals together releases the energy, also in the form of heat)
I hope that all makes sense
