I worked on a mining project years ago where we had to dewater the mine of 90 degree Celsius water at 700L/s.
Always wondered whether we can use it for energy….
Always wondered whether we can use it for energy….
As the article mentions, you need to get above the phase transition between liquid and gas at high pressure (they mention 150c) to be able to reliably and quickly convert the thermal energy into kinetic, then into electrical inductance (gas expansion moving a turbine, moving a dynamo).
Maybe if you went into business making pot roast, you could cook meat low and slow, or set up massive dehydrators.
Running it under a shallow drying bed might make salt extraction from water evaporation faster, too.
Sadly, none of those things tend to be very close to mines.
Problem is that mature turbines are designed for steam. Turbines for other fluids cannot approach their market volume.
Steam is used everywhere despite that it is quite corrosive, mainly because it is cheap.
Cold distilled water is not corrosive. Superheated steam, howsoever pure, little resembles cold liquid water in any detail. Furthermore, hot water will pick up minerals from whatever it runs through.
Many materials that are not especially corrosive as cold liquids behave quite differently at extreme pressure and temperature. Water has uncommon valuable thermodynamic properties, but not uniquely so; its chief virtue is that it is good enough and cheap.
Gas turbines are common when power to weight is more important than cost.
Say ambient air is 20 deg C, with your 90 deg C heat source then you get 1-293/363 which is about 20%. So it's not to say you can't get work out of this system, but it's not great compared to having something nice and not.
And even then, you can't push a turbine with a hot liquid so your energy extraction technique now gets complicated.
I use to scoff, but turkey sous vided is yummy