[epistasis]

If it's the startup I'm thinking of, they've done most of their work on the downstream process of converting CO2 to useful things, rather than focusing on capture. The energy used in capture of CO2 is only a fraction of the cost of changing CO2 into a sequesterable form or fuel form.

That said, this is a really great idea, as heat pumps will be increasingly used for all sorts of temperature management. Cutting 10% off of costs by using somebody else's fans could be great, as long as hauling the CO2 filters off and replacing them is cheap.