Power Station With Alcohol Second Stage

Power stations are simple machines. First, you acquire a source of heat. Burning things is the traditional approach but there's also nuclear fission, geothermal and a couple of variations of solar. The heat is then used to boil water and make pressurized steam. This has been the gold standard for a long time, since Newcomon was a lad.

Steam is good at making things move, pistons were fashionable while chaps with regional British accents were inventing the Industrial revolution*. Subsequently, the steam turbine was invented by a British chap with probably a non-regional accent. He immediately attached it to an electrical generator** and things haven't changed much since.

So, a power station might involve the burning of gas, the boiling of water to make pressurized steam, passage of that steam through a turbine and.... well, you could just let it out the back, but then you'd waste the nice, pure and expensive water. Instead, they route the steam through pipes immersed in pools of regular water until it condenses, then pipe it back to the start of the loop. This is a good system, you can recycle the pure water and condensing at the back of the turbine makes a lovely pressure gradient.

Sadly, condensing steam heats the cooling water and it evaporates in huge clouds out of the cooling towers so often seen at power stations. This is wasted energy. Quite a lot of it. There have been schemes to distribute this spare heat, heating nearby communities and such but almost always it is just dumped to the atmosphere.

Now, the sort of turbines power stations operate have an exhaust temperature around 75C range as far as I can work out. This can be used to boil a range of liquids but ethanol and methanol spring to mind. Using your exhaust steam you can boil alcohol to create whole lot of pressurized alcohol vapor*** while condensing your primary circuit MORE efficiently. This alcohol vapor may spin another turbine and another generator. After this, you'll need to condense your alcohol vapor to get the optimal delta p across the turbine, just like the steam in a normal station. This will have a smaller temperature differential, so the cooling tower will be less efficient, but the total heat being rejected is now smaller, so probably a swings and roundabouts situation. Anyhow, if it doesn't work I've got plans for a 3rd stage using ether.... while Canada/Russia/Scandiwegia may be interested in my Butane 4th stage.

Once this is up and running, small amounts of alcohol might be drawn off and sold in the gift shop for those who really appreciate efficiency, and booze with just a hint of dissolved turbine lubricant.

*The crank was key here, before that industry was entirely linear. Progress was constrained by the number of young boys available to retrieve and re-install pistons. **Attaching one to a battleship caused a bit of a kerfuffle in the Naval world. ***Annoying how "steam" only applies to water..