Can we use the heat to boil water to turn a turbine? Or would the water never cool enough to be used again?
What about using the heat to create pressure and then releasing the pressure to help move the fly wheel?
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I’ve always wondered about sticking peltier devices to the exhaust and charging up lithium batteries from it
We already do. Turbochargers use energy that would otherwise be wasted to pressurize the intake tract. This increases power and efficiency. It allows a small engine to do the work of a much larger naturally aspirated engine.
[A more in-depth explanation ](https://auto.howstuffworks.com/turbo.htm).
I think it might’ve been Volvo? Years ago I saw they designed a 5 cycle gasoline engine. The fifth cycle was water. It used the residual heat from the gasoline combustion to flash boil water in the cylinder. I don’t remember much about it but I thought it was cool.
This is Watt idea. The steam machine. Is OK, it works. In fact, the first car was like this. The problem is the performance, or efficiency. The percentage of energy you transform in work from the combustible energy.
If you are making a big machine such as a power plant, this is the best idea. Have best efficiency. If the machine is little, the best is two times gasoline engine. Like little motorbikes, is the power is a little bigger, is better 4 times gasoline, bigger, diesel, for example little ships. And only in a very big machine the steam machine is better
Because the main inefficiency in cars is that you’re using 4000lbs of steel to move a 200lb person. If you want to buy a gallon of milk, you’re moving 4200lbs of material several miles to secure 8lbs of milk. It doesn’t matter how close you get to Carnot optimal, you’ve wasted 99.8% of your energy moving things that weren’t part of the objective.
And practical efficiencies in Carnot cycles require scale. The larger the engine the more efficient you can usually make it, which if you’re an engineer chasing a regulation of ‘x MPG at highway speeds’ competing with a regulation of ‘can survive a front-end collision at highway speeds’, then there are certain realities with respect to mass and power you need to accept to meet the assumptions in this calculation (that people need to travel in cars at highway speeds on infrastructure so poor that a head on collision is a likely enough occurrence that it needs to be protected against.
Note the regulations don’t say ‘don’t build a society where you need to burn a gallon of gas to secure a gallon of milk’.
There are no technical obstacles to running an energy efficiency society. All of the obstacles are cultural. We have inefficient cars because we demand inefficient cars. You had 60MPG cars in the US in the 80s. They were small, didn’t accelerate fast, and often couldn’t hit Texas highway speeds. There are more efficient cars in Europe – basically all the most popular cars in Europe are pretty efficient. None of them are sold in the US because Americans want road tanks, because we favor personal survivability over efficiency, economy, survivability of the community (pedestrians, cyclists, people who do buy small cars) and so on. Cars are inefficient because we want them to be, not because we can’t solve the problem. Climate change is a cultural, not technological problem. We know how to solve climate change. Have for quite a while. Homelessness is a cultural, not technological problem. We know how to solve that too. Same with healthcare costs, and almost everything else.
But we already do it.
Turbochargers harvest excess energy that comes out the exhaust and use it to pump more air into the intake, aiding combustion
Not enough heat
Also why we can’t use the heat generated by our phones to charge our phones
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