I've seen a lot of references to films which radiate heat from an underlying surface out into space. For example:
- http://radi-cool.com/
- https://arpa-e.energy.gov/technologies/projects/passive-radiative-cooling-film
- https://www.skycoolsystems.com/
Some papers/companies seem to claim this technology could be sufficient to cool a house with only the energy usage of a small pump to circulate coolant. But are any of these technologies available for residential use yet? Every company I have found only does commercial.
