Why is the Orangerie in Versailles a good place to sleep in summer AND winter?
First, the Orangerie is in Paris, not in Versailles. It is an art museum so the question about sleeping there is unusual. Did you mean to ask if these are good places to visit?
Both the Orangerie and Versailles are endlessly fascinating places to visit. The beds in Versailes are not for the visitors, though--they are museum pieces.
You would need to find a hotel near either of these museums and landmarks.