Comment on Why can't countries with vast deserts make solar farms to power the world?
mrgoosmoos@lemmy.ca 14 hours agoThe only thing that makes sense is that they absorb heat that would otherwise be reflected away, right?
in the building example, they’re essentially insulated against a specific mass by air gap behind them, and in the heat island example, the area of concern is larger and the panels are included.
porksnort@slrpnk.net 13 hours ago
How is dirt different from a building in terms of thermal mass? It’s the same setup. Panels can shade buildings just as well as dirt. It’s actually a super complex situation that depends on a huge number of variables.
I’m pushing back because this common trope (solar panels cause heat islands) was part of a whirlwind of anti-solar FUD about a decade ago.
The moronosphere turned some wonky studies that showed some local heating effect (in some situations, not all) into a panic about it causing mega-storms and causing dogs and cats to want to live together.
Since then, actual experts have been working hard to understand the costs and benefits of large installations.
An example:
Agrivoltaics
XeroxCool@lemmy.world 13 hours ago
Have you been in a desert at night? It gets cold, fast. Have you ever dug a few inches down into sand and touched it? It’s much colder than the blazing surface in the summer. Deserts to not typically have dirt, they have sand. Black panels shading a typically black roof will of course decouple the heating from the building. Black panels shading a very pale, very reflective, very insulative ground material is going to absorb and retain more heat
mrgoosmoos@lemmy.ca 13 hours ago
When attached to a building, the panels transmit a small amount of the absorbed heat to the building - less than would otherwise be absorbed by the building if the panels were not shading it. The building’s thermal energy is what is being measured, not that of the space including the solar panels.
When in an open space, the panels absorb more heat than would otherwise be reflected out of that space if they were not there, but they contribute to the total thermal energy of that space.