The home office solar panel depreciation appears automatically as a 39 year property on part III line 19i on form 4562. Based on Pub 946 I would expect to see it on line 19b as a 5 year property with a higher depreciation deduction.
Since it is part of your home office and part of your home, it is presumably depreciating it like the remainder of the house. If the solar panel are just for your office and were put in for business use, you can include as a separate asset in Business Assets. I would not do this unless specifically used for your office.