The offerings from Mitsubishi and similar ones from other Asian manufacturers like LG and Fujitsu are air source heat pumps. I see no reason why the tech can't

The offerings from Mitsubishi and similar ones from other Asian manufacturers like LG and Fujitsu are air source heat pumps. I see no reason why the tech can't be scaled down to fit a car. It's certainly a reasonable goal for auto parts suppliers to aim at.