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Comment by uranium | Hacker News Reader

I presume you're using a heat exchanger to cool the exhaust and heat the discharging pellets. How big a temperature differential are you getting from the exchanger? How much extra energy do you need to put in for cooling? At switchover, how do you cool the pellets that you've just finished heating? Is the heating-compression cycle a lot faster than the collection cycle?

Given the overhead and hassle of putting small units on a huge number of trucks, how does this compare to just putting a small number of larger units on power plants or furnaces?

--How important is the CO2 concentration in the exhaust? Is this something that could be done just from atmospheric CO2, not on a concentrated source?--[Edit: Already addressed below.]

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this is a very detailed and thoughtful question!

We have 2 or more chambers, we are balancing the number of chambers so that a chamber is always adsorbing while the other one (or 2) is transitioning temperature or holding a hot cycle to regenerate.

We adsorb at ambient temperature so cooling the previously heated device is not too much energy, mostly just a fan, but there is some available cool refrigerant from our dehumidifier/heat pump cycle that removes moisture from the exhaust to help quickly drop the chamber temperature.

We can use the exhaust waste heat to start heating the bed that is going into the hot regen cycle, then we use the waste heat from our exhaust dehumidifier to get the bed the rest of the way to the target hot cycle temperature.

Its hard to explain in text, but you can see that we get to use the hot and cold cycles from the refrigerant cycle to do work for us simultaneously and take advantage of the heat in the exhaust itself!

Thanks, that's quite clear.

What about the tradeoff vs. large stationary units on power plants? I know other folks are working on that as well; would love to know about how the economics work out vs. truck-sized units.

The great thing about truck-sized units is that they can be modular, so we can easily mass produce them. The challenge with stationary units for power plants is that each one has to be custom-designed from the ground up. Plus, you have to put in tons of capital up front for a power plant, whereas our units are very cheap to make. That's why we think mobile carbon capture is the more scalable approach.

It seems like integration with small generators could happen later, though? Perhaps concrete producers or other consumers of CO2 would buy them, and use or sell the electricity.

integration with generators at the CO2 consumers site, cut out the shipping costs, that's an interesting thought experiment!

That makes a lot of sense.

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