31
If we can use hydrogen to power electric motors, why can’t we use water to run a car?
(self.nostupidquestions)
this post was submitted on 14 Feb 2024
31 points (81.6% liked)
No Stupid Questions
36134 readers
835 users here now
No such thing. Ask away!
!nostupidquestions is a community dedicated to being helpful and answering each others' questions on various topics.
The rules for posting and commenting, besides the rules defined here for lemmy.world, are as follows:
Rules (interactive)
Rule 1- All posts must be legitimate questions. All post titles must include a question.
All posts must be legitimate questions, and all post titles must include a question. Questions that are joke or trolling questions, memes, song lyrics as title, etc. are not allowed here. See Rule 6 for all exceptions.
Rule 2- Your question subject cannot be illegal or NSFW material.
Your question subject cannot be illegal or NSFW material. You will be warned first, banned second.
Rule 3- Do not seek mental, medical and professional help here.
Do not seek mental, medical and professional help here. Breaking this rule will not get you or your post removed, but it will put you at risk, and possibly in danger.
Rule 4- No self promotion or upvote-farming of any kind.
That's it.
Rule 5- No baiting or sealioning or promoting an agenda.
Questions which, instead of being of an innocuous nature, are specifically intended (based on reports and in the opinion of our crack moderation team) to bait users into ideological wars on charged political topics will be removed and the authors warned - or banned - depending on severity.
Rule 6- Regarding META posts and joke questions.
Provided it is about the community itself, you may post non-question posts using the [META] tag on your post title.
On fridays, you are allowed to post meme and troll questions, on the condition that it's in text format only, and conforms with our other rules. These posts MUST include the [NSQ Friday] tag in their title.
If you post a serious question on friday and are looking only for legitimate answers, then please include the [Serious] tag on your post. Irrelevant replies will then be removed by moderators.
Rule 7- You can't intentionally annoy, mock, or harass other members.
If you intentionally annoy, mock, harass, or discriminate against any individual member, you will be removed.
Likewise, if you are a member, sympathiser or a resemblant of a movement that is known to largely hate, mock, discriminate against, and/or want to take lives of a group of people, and you were provably vocal about your hate, then you will be banned on sight.
Rule 8- All comments should try to stay relevant to their parent content.
Rule 9- Reposts from other platforms are not allowed.
Let everyone have their own content.
Rule 10- Majority of bots aren't allowed to participate here.
Credits
Our breathtaking icon was bestowed upon us by @Cevilia!
The greatest banner of all time: by @TheOneWithTheHair!
founded 2 years ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
Because it will always take more energy to break the water than you will get burning the Hydrogen in Oxygen back into water - it's basic thermodynamics.
You will lose some energy as heat that you cannot get back*.
You can't power a car from a process that loses energy. Even if you use a battery to donate the lost energy, then you might as well just cut out the lossy middleman and just run off the battery or generate the Hydrogen elsewhere - which is what we currently do.
It is better to think of Hydrogen as an energy transporter than as a fuel, as you'd need to generate the Hydrogen somewhere that has abundant energy (ideally renewable), then transport I where needed, such as a Hydrogen powered generator.
*Interestingly the fact that all processes generate waste heat means the only theoretically 100% energy efficient process is heat generation itself, as all forms of energy eventually degrade to heat (as it is essentially the universe's waste energy).
Electric heaters aren't 100% efficient, because some of the energy is wasted altering the resistive material chemistry and emitting other electromagnetic radiation, and even sound, that doesn't heat the air inside your house (right away). Still at a perfect 100% efficiency, it takes 1 joule to raise your house temperature by 1 joule, ideally. Heat pumps, which are just an AC unit running in reverse, are more efficient than electric heaters. Some heat pumps have a coefficient of 3. Meaning they take 1 joule to heat the air in your house by 3 joules. Because they don't try to heat the air, they move heat to the air from outside, and they can achieve this even if outside is freezing.
That's the theoretically part - there are processes that will capture the energy generated that would've otherwise become heat, but that only affects the timeliness. Given enough time, all workable energy generated by a heater would become heat, even if you had to wait for the matter itself to decay trillions of years from now when all the stars have long since breathed their last breath.
Also has somebody watched Technology Connections by any chance?
Heat pumps are so cool - if you showed onw to someone even a hundred years ago, even knowing what electricity was, they'd think it was magic.