[mncharity]

The OP prompted me to check on Shanhui Fan's group[1], which had done some sub-ambient radiative cooling in sunlight[2], and I stumbled on this recent work:

A dual-mode textile for human body radiative heating and cooling[3]

[1] https://web.stanford.edu/group/fan/ [2] https://web.stanford.edu/group/fan/publication/Goldstein_Nat... [3] https://web.stanford.edu/group/fan/publication/Hsu_ScienceAd...