It (rehab) doesn't work well in relation to homes. Although it's used, it's just not as common as renovation, remodelling or improvement (as some examples). And also the connotations of drug, mental, physical, etc, rehab are going to be in people's mind. So for that (solar panels) purpose I don't see any value in it.
So, could it work for a travel/holiday site? Perhaps, rehab on a sunny beach in a beautiful resort specifically orientated towards helping you relieve stress and/or getting back into good physical condition.