I conduct a systems-level study of direct air capture of CO2 using techniques from thermal physics. This system relies on a combination of an efficient heat exchanger, radiative cooling, and refrigeration, all at industrial scale and operated in environments at low ambient temperatures. While technological developments will be required for such a system to operate efficiently, those developments rest on a long history of refrigeration expertise and technology, and they can be developed and tested at modest scale. I estimate that the energy required to remove CO2 via this approach is comparable to direct air capture by other techniques. The most challenging aspect of building a system that could remove 1 billion tonnes of CO2 from the atmosphere per year is the power demand of 112 to 420 GW during the wintertime operational period.
Scholarly Commons Citation
von Hippel, T. (2018). Thermal Removal of Carbon Dioxide from the Atmosphere: Energy Requirements and Scaling Issues. Climatic Change, 148(4). https://doi.org/10.1007/s10584-018-2208-0