Using the electrolysis of water to cool a room

Question

Browsing the internet yesterday I came across this very esoteric paper which purports to describe the construction of a device which uses the electrolysis of water into hydrogen and oxygen (a highly endothermic process) with KOH as a catalyst to cool down a room as a replacement for an Air Conditioner: https://www.researchpublish.com/upload/book/Electrolysis%20Air%20Cooler-3057.pdf

The enthalpy of the reaction is +285.83 kJ/mol, and while most of the energy input comes from the electricity being supplied, a fair portion (around 20%) comes from heat in the surroundings at standard temperatures so the basic chemistry/physics is there:

As stated, splitting a mole of liquid water to produce a mole of hydrogen at 25°C requires 285.8 kJ of energy—237.2 kJ as electricity and 48.6 kJ as heat.

Reference for this: https://www.nrel.gov/docs/fy10osti/47302.pdf

The authors of the paper describe the construction of such a device as well as a test showing that it is indeed capable of reducing temperatures inside a room (the paper itself is not well written so a lot of things are unclear, but they definitely did get the idea to work )

I found the idea quite intriguing, especially given that it generates hydrogen which can be stored to be used later as a fuel. I was not able to find any other references to this idea on the internet, which makes me suspect there is something else going on which makes the idea impractical for why other people haven't independently come up with the same thing and developed it further but I can't think of anything except for the hydrogen gas generated being an explosive hazard (but that can be stored/vented away so shouldn't be a big issue).

So, is this idea viable, or is there something big I'm missing?

Answer 1

There's a reason no one has heard of this

1. Electrolysis doesn't absorb heat from its environment. The change in energy state between water and hydrogen/oxygen gas is equal to the electrical energy you put into them. If we could create hydrogen gas via cooling our surroundings we would have discovered essentially free unlimited energy. We can't, and we haven't.

2. Putting hydrogen and oxygen into your home would be a terrible idea. This would be the equivalent of using an open methane pipe to cool your home. Even if it worked you're introducing a highly flammable gas to your home. The nickname of the oxygen generator (which used electrolysis) on my old submarine was nicknamed The Bomb for exactly this reason.

Answer 2

You have referenced a process with a Co-efficient Of Performance of 0.25. According to Wikipedia, "Most air conditioners have a COP of 2.3 to 3.5"

You suggest that, if the energy could be recovered from the separated hydrogen and oxygen, you could get an improved COP.

If what you want to do is "cool a room", electrolysis of water is an extremely ineffective way of doing so, even with the referenced catalyst.

There are other similar cooling systems that work on chemical association/dissociation rather than phase change. It's not a crazy idea. And, as you suggest, hydrogen generation is currently an area of high interest. But using this process for room cooling is not something that, at present, would interest anybody who actually wanted to cool a room.