So I work at an office that is constantly warm in the summer, especially when the sun is facing the window. It has blinds, but those blinds aren't fully reflective, and I'm not sure if there is any legal liability to putting tinfoil outside them.

 

However, there is another tinfoil-involving alternative that might work; indoor concave mirrors to collect solar energy.

 

https://www.youtube.com/watch?v=8CLRTa_ocmo

 

I'm thinking if I did something less precise, but still in a general concave shape, to concentrate all the solar radiation entering the office through the window on a darkly coloured kettle and use this to boil water for coffee or tea.... if I and/or my colleagues were to drink that tea or coffee, would the general effect on how warm it feels in the office, including the heat from the coffee I'm drinking, make it equivalent to the warmth from if all that solar radiation were absorbed by the walls or floors, or would the net effect be a cooling effect?

 

(Disclaimer: I intend to ask my boss well before going through with it... but I intend to ask you guys well before asking my boss.)

Unless you heat the water and then remove it from the room, it won't have a cooling effect. You would just be moving the thermal energy around, but it will still be there.

Very well, thanks for letting me know.

I've been doing Mylar over cardboard, for the inside of mine lately. Might be easier to get your boss to agree to that.

Edited August 14, 20205 yr by Endy0816

The room would be (very) slightly cooler than if you had heated the water electrically, all other factors being the same.

Any reflecting or shading treatment should only be done at the exterior; before sunlight hits the windows glass.  That produces a considerable cooling !