Hi,
First of all, the basis of this idea or not electronic related. I know there are plenty of forum about renewable energy but I find there are way too many people in them who don't have a clue about thermodynamics or conservation of matter/energy.
The idea is that sodium hydroxide, when mixed with water releases heat, a substantial amount of it. In theory, you can evaporate the water and combine them again an infinite amount of time.
That has been used in what was called soda locomotives. Where two tanks, one containing water heated up to steam and the other containing caustic soda were thermally coupled. The steam, after doing some work was condensed and added to the caustic soda to release heat, keeping the steam coming.
Though that part is relatively well documented, I cannot find anything about how they were regenerating the sodium hydroxide.
I have been playing with the idea of applying this to heat storage. From summer to winter of even from day to night.
What I picture is a closed loop system, similar to an ammonia fridge, with one tank containing the hydroxyde solution and the other containing the water, when heat is available (solar heat, excess solar electricity, air conditioner's heat exhaust, wood furnace) the water would be evaporated from the solution and condensed on the other side.
And then, I see two practical options (or a combination of both):
The "simplest" would be that when heat is needed, water would be pumped from the water tank to the solution tank as needed while the heat is pumped out.
The more complicated, much harder to manage would be to transfer the concentrated solution to a water boiler to generate some steam.
Does anyone has any experience or literature about anything related to this?
Mainly the regeneration process, how to stop the sodium hydroxide from producing aerosols and contaminate the water tank?
What material are suitable for a hot and caustic environment?
What are the options in case of catastrophic failure of the system? You can obviously not douse it with water.
Are there any legal issues regarding the storage of sodium hydroxide in relatively big quantities? In Australia, just in case you wondered.
(say 1 to 5 tonnes, which would represent a capacity of storing up to, respectively, 0.3 to 1.5 MWh in chemical energy if I didn't stuff up my math, that's not accounting for thermal energy storage)