No, like a steam engine providing electricity for the vapour compression refrigerator. Since I don't know what a pressure vessel is and how it makes energy, and you didn't tell me, I replaced it with a steam engine because I know it. So, cold water gets heated, the steam is used to drive a rotor, which is converted to electricity, which is used to power the vapour compressed refrigerator, which cools the water back down. Classical perpetual motion machine. If this worked, we wouldn't go through all the trouble to use solar, nuclear, coal and wind energy.
That's what the second law of thermodynamics states. If you could make energy from heat your PC would use no electricity – you would use the heat generated by the CPU to power up the PC. And the heat generated by the EM radiation coming from the monitor. In the winter, you'd extract heat from the outside (reducing the temperature there) to make electricity and subsequently heat your home, again without any electricity.
You'd make energy from the heat and power it? Except for a little bit of EM radiation, all the energy the CPU uses is released back as heat. If you could turn that heat back into useful energy, you wouldn't need any additional energy to power up that CPU.
I think your example is a bit ad hoc. However you win the heat argument. But then. There's an awful lot more powerful wind on Venus than there is on Mars ...
Rather Venus than Mars, which will remain useless. Too little gravitation to keep a substantial atmosphere, not much to make it from in the first place, too little water and nothing to extract more from, no magnetic field. Life on Mars will take place indoors only. One technology to clean Venus' atmosphere from C02 and thereby removing the greenhouse problem which isn't SF already exists, "artifical trees". We might possibly see millions of them soon here on Earth to fight our CO2 problem. There isn't much water vapor in % in it's atmosphere, but the value has to be multiplied by about 100, that's how much denser Venus' atmosphere is at the surface than Earth's. Enough to cover much of the planet with shallow oceans, it's whole landscape is as amazing and hilly as the American Midwest. The oxygination could reduce the surface pressure to 3 bar; dissolving nitrogen in liqid water, and binding oxygen in all sorts of stable compounds naturally would reduce it further. Still, the long solar day, and maybe because of it weak magnetic field remain.
I stand corrected for the surface winds. After checking, they are more powerful/faster than what I expected. They are very slow, but still quite powerful. You could set up a hardened wind power plant there, though I'm not sure how big it will have to be to produce any significant energy. The idea about a surface Venusian colony is quite fascinating, because of how crazy it is when I picture it – think about wind turbines going on for miles and miles powering up a small colony at the middle, creating a small paradise in the middle of hell. Still, the cloud tops and Mars are better choices...
The only way Venus could be colonised is underground, IMO. You need to protect little squashy bodies from the atmosphere with something more substantial than man-made structures.
Well, what's interesting is oxygen is buoyant on Venus. You could have floating cities filled with earth air. Not sure what that gets you, but it's true.
A space colony is vulnerable to debris and micrometeorites. You also need to keep the temperature at certain limits manually, by heating and cooling. Repairs on the outside require pressure suits. A space station has to be fully pressurized and any leak is an extremely serious issue. It's also too exposed should we be attacked by aliens in a billion years -- or by ourselves for that matter. Not to mention that the view is less homely in space, and there's that gravity thing. If it floats in the atmosphere of Venus it might make sense to park it there. If it works in space, and it floats, it's better off in the atmosphere. You get free temperature moderator, free protection from flying junk, free weight (i.e. gravity), you can walk outside with a simple oxygen mask for short periods of time, you have more time to repair leaks, you get free clouds in the window and all these cool things. That said, large O'Neill colonies don't require pressurization and aren't afraid of micrometeorites.