One way to visualize this is to imagine the losses involved are like the frictional losses in a rotating system like a wheel. If we simplify the system to just the wheel, a fixed shaft, and a bearing. No matter how low friction the bearing is, it can’t be frictionless. If you spin the wheel, it will begin to slow right away, and eventually stop. This could take a long time, but it is inevitable.

The energy that is ”lost” is actually not lost of course. But since we have a goal for it, the energy that is turned to heat is “lost” to us. Now ask your initial question about this system, what if we stored up the lost energy and used it somewhere else?

To do this, we’d have to store heat, or convert the heat to something else, like electrical current we store in a capacitor, or use to spin up a flywheel. Right away, we can see that anything like that will also be lossy, but can’t we at least come out ahead after the input and output losses?

No, because energy is not free and any additional load we place on the system, anywhere, requires energy from somewhere to work. We will never be ahead of maximizing the initial efficiency of the original system and simply putting less energy in to start!

One example recovering some input energy is regenerative braking where a propulsion motor is turned into a generator which causes is it to act like a brake, and the output is used to charge the battery. There is still loss all along the way, but less. Schemes like this are as close as you can get to preventing losses but it only works for energy that is accumulated in the powered system and is not needed—like momentum.

The laws of thermodynamics are strictly enforced and there is no appellate court in physics.

 

One way to visualize this is to imagine the losses involved are like the frictional losses in a rotating system like a wheel. If we simplify the system to just the wheel, a fixed shaft, and a bearing. No matter how low friction the bearing is, it can’t be frictionless. If you spin the wheel, it will begin to slow right away, and eventually stop. This could take a long time, but it is inevitable.

The energy that is ”lost” is actually not lost of course. But since we have a goal for it, the energy that is turned to heat is “lost” to us. Now ask your initial question about this system, what if we stored up the lost energy and used it somewhere else?

To do this, we’d have to store heat, or convert the heat to something else, like electrical current we store in a capacitor, or use to spin up a flywheel. Right away, we can see that anything like that will also be lossy, but can’t we at least come out ahead after the input and output losses?

No, because energy is not free and any additional load we place on the system, anywhere, requires energy from somewhere to work. We will never be ahead of maximizing the initial efficiency of the original system and simply putting less energy in to start!

One example recovering some input energy is regenerative braking where a propulsion motor is turned into a generator which causes is it to act like a brake, and the output is used to charge the battery. There is still loss all along the way, but less. Schemes like this are as close as you can get to preventing losses but it only works for energy that is accumulated in the powered system and is not needed—like momentum.

The laws of thermodynamics are strictly enforced and there is no appellate court in physics.

More importantly, there is no possible appeal to a higher authority.

 

note that 12 volts DC has not been a part of this thread. And certainly a heating appliance like a microwave oven can use power that is not a perfect sine wave. And while most of them provide a turntable with a motor, they do not require that to be usable.
The power source is a "traction battery" with a voltage that drops from 270 volts to 200 volts as it discharges. There is no mention of how it gets recharged, at least not yet.
It appears that the Panasonic brand "inverter" models of microwave oven us rectified mains power to feed an inverter, as the package does notinclude any mains frequency transformers. So a microwave oven operating on 200+ volts DC appears to be available.

Hi,

I have to disagree on the part where you said, "turntable is not required to be useable".
With my oven, and i have a Panasonic Inverter type BTW, if i did not use the turntable my food would cook much more on one side than the other. The turntable allows the foot area to get an average power heating by rotating the food so both sides get high and then lower in turn, and the average is what makes the food cook even. Without that, I'd hate to see what a hamburger patty looked like after cooking. Maybe turn it yourself every 20 seconds? Be a bit of a pain to have to use it that way.

As to the issue of 12v never being part of this thread, i guess you missed post #16.

The price of pure sinewave converters has come down a lot in the past couple years or so. I think you can get a 1000 watt unit for under $100 USD.

 

Hi,

I have to disagree on the part where you said, "turntable is not required to be useable".
With my oven, and i have a Panasonic Inverter type BTW, if i did not use the turntable my food would cook much more on one side than the other. The turntable allows the foot area to get an average power heating by rotating the food so both sides get high and then lower in turn, and the average is what makes the food cook even. Without that, I'd hate to see what a hamburger patty looked like after cooking. Maybe turn it yourself every 20 seconds? Be a bit of a pain to have to use it that way.

As to the issue of 12v never being part of this thread, i guess you missed post #16.

The price of pure sinewave converters has come down a lot in the past couple years or so. I think you can get a 1000 watt unit for under $100 USD.

I never said as convenient as with a turntable, but amazingly enough we learned to cook food very well prior to when turntables became common. But certainly working around the limitations of some appliance can be achieved by many folks, although a fair number will never ever discover how it can be done. That is how natural selection works, at least how it is supposed to work.
I have cooked pizzas quite well in a microwave oven prior to turntables. It was not as simple but it certainly was possible.