[scarytom]

Burning the propane takes you back to CO2, which you then turn back into propane again and repeat? If your napkin maths is correct, and the process is net energy positive, doesn't this violate the principle of conservation of energy?

It must take at least as much energy to turn carbon dioxide into propane as you generate when you burn that propane to generate carbon dioxide.

[8fingerlouie]

> If your napkin maths is correct, and the process is net energy positive, doesn't this violate the principle of conservation of energy?

In theory, yes, but you need to take into account all the energy that goes into the process, which includes the catalyst, and also the actual capture of the CO2.

The way i read it, this is "just" a way of turning already captured CO2 into fuel again in an efficient way.

Still, it does seem a little bit too good that you can obtain 3 kWh of energy by spending 1.6 kWh, but i guess time will tell.

[goodcanadian]

This is just an educated guess, but . . .

Burning propane produces CO2 AND water. I think the missing bit is the energy required to split the water into hydrogen and oxygen before the hydrogen is used as an input to produce the propane.

[sveme]

Heat pumps can create 3 - 5kWh of heat from 1kWh of electrical energy.

[8fingerlouie]

Heat pumps do not create heat, they simply move heat from one place to another, which is an entirely different beast.

Using a traditional resistive heater, you're roughly creating 1 kWh of heat by spending 1 kWh of electricity (there is some loss), but with a heat pump you're moving heat, which is also why heat pumps become much less efficient the colder the temperature as there is less heat to move, and many residential heat pumps include a regular resistive heating element as a backup.

There's a great explanatory video on how heat pumps work here : https://www.youtube.com/watch?v=7J52mDjZzto&pp=ygUgdGVjaG5vb...

[sveme]

Good point, thanks for the correction.

[RetroTechie]

Correction: heat pumps pump heat from 1 place to another. As in: place where it gets pumped out of, gets colder.

Fundamentally different process from exothermal chemical reaction, or electric heating using resistive wire.

[sveme]

Isn't the input electrical energy and the output of burning the propane heat? If you convert the heat back to electrical energy, you get much less than you input into the reaction.