[sidewndr46]

The only practical way to do such a thing would be with a giant mirror. There is no reason why earth cannot radiate energy back into space. A mirror is a good way to do that for the optical wavelengths. Most of the energy received by earth each day is in the optical spectrum and secondarily from the gravitational interaction of the earth-moon system. The moon we can't really do much about. But sunlight absolutely can be reflected.

A mirror would also be much more effective if part of some ring like structure orbiting the earth, as most of the energy would never enter encounter earth's atmosphere in the first place.