Comment on Why can't countries with vast deserts make solar farms to power the world?
ChaoticNeutralCzech@feddit.org 6 days agoThey’re black, duh. Yes, some 20% of incoming energy becomes electricity but the rest gets turned into heat. A reflective (white) material heats up way less.
porksnort@slrpnk.net 6 days ago
So you ignored the fact that it’s not the earth that is getting heated, it’s the panels. So when the sun goes down the thin panels and the air around them cool down quickly, much more quickly than a large mass of hot rocks and dirt.
‘Thermal mass’ is a huge factor here. You ignored the basic finding that buildings with panels on the roof are cheaper to cool just because of the shading effect of the panels.
ChaoticNeutralCzech@feddit.org 6 days ago
Panels are effectively part of the earth. It’s one closed system.
You do have a point: a black body radiates more heat than a high-albedo one so at night, the panels can cool down below ambient temperature. Overall, low albedo (reflectivity) and small thermal mass causes higher temperature differences between day and night – and it’s daytime when people want cooler temperatures.
But yes, any shade will help people living below solar panels feel cooler on sunny days, which is why I advocate for building a solar roof over just about every parking lot.