xombie25 OP t1_j1wtu9e wrote on December 28, 2022 at 12:02 AM

The reaction from limestone with water is exothermic. As an example. Limestone is plentiful, water is plentiful. I guess the point of a chemical reaction is that it eventually we just run out of reactants. And that is not sustainable.

I wonder if there was some kind of recycling loophole you could design for a very low loss energy production cycle. Seems like it should be possible at least somehow.

anglesideside1 t1_j1wvl5g wrote on December 28, 2022 at 12:15 AM

The hardest part of creating a perpetual motion machine is figuring out where to hide the motor.

NortWind t1_j1x4th5 wrote on December 28, 2022 at 1:24 AM

The reaction from limestone with water is endothermic, it consumes energy. Limestone is made by tiny fossil shells piling up on the ocean bottom.

capt_yellowbeard t1_j1x8oo7 wrote on December 28, 2022 at 1:54 AM

Actually this isn’t quite correct. The limestone must first be burned to make calcium oxide (that is energy in) and then when it’s mixed it creates an exothermic reaction when hardening.

Limestone is itself already chemically similar to hardened concrete.

NortWind t1_j1x9c1l wrote on December 28, 2022 at 1:59 AM

Right. But that is not limestone reacting with water, it is CaO (aka quicklime) reacting with water.

capt_yellowbeard t1_j1x9qd2 wrote on December 28, 2022 at 2:02 AM

Yeah. That’s what I said.