Whether your AC recently broke or you just need some extra cool air, there’s one deal you should definitely take advantage of this Amazon Prime Day: a portable air conditioner that’s 30 percent off.

Costco accepts most returns without time limits, though there are some exceptions. Electronics have a 90-day return window.

As the penetration of renewable energy resources increases, their intrinsic uncertainty and randomness raise significant concerns about the grid’s reliability. With the development of information ...