Reversing the energy flow?

I don't know if I will ever find the answer to this question, but I thought here would be a good place as any to get an answer.
Well the question is: How can the energy flow be reversed? What does it actually mean to "reverse the energy flow"? Could it just mean to reverse the polarity of the connections? Or could it mean that energy needs to flow from the lower entropy state to the higher entropy? How could that be done? This is the typical place that getting one answer just gets you more questions.

I wanted to make something, this something would be electronic and would also have cpus (probably many of them), and someone told me "Reversing the energy flow is the prerequisite to making the said item" So if anyone can help me figure out what he meant please help me.

Before anyone says I would like to say it is next to impossible to ask the same person for details.

What is the intended end result? Output? Input? Reversing the energy flow could mean ANYTHING without some sort of context. It could mean putting your car into reverse or blowing milk out your nose lol

If you are talking about thermodynamics, then according to traditional science and the second law of thermodynamics reversing the energy flow is not possible. There are many processes that conserve energy spontaneously in nature, but do not happen in reverse. I mean, for example, if heat were to leave a colder object and pass into a hotter one, energy would still be conserved, but it never happens. So it depends on what you are talking about. With entropy, an isolated system will either stay constant or increase. It will never decrease, so that means its an irreversible process. So it depends on your application. My guess is that its not possible, but if you provided more details it would be easier to answer your question. If you find a way to break the traditional laws, then let me know .

Reversing the energy? No idea.
Using CPUs? Perhaps try microcontrollers instead?

On various electronic devices - microcontrollers for example, you often need positive and negative supplies to power the device, but you usually have a single power source (say a battery) which only delivers positive. In such case you would need to have a circuit that flips the positive voltage from the battery and makes it negative. Maybe that's what he meant?