Macro to close and re-open a workbook at specific time

The code would need some sort of host application to contain it; if you close a workbook that contains code it will immediately halt the execution of that code.

I'd consider placing the code in another spreadsheet, but you'd still be running code nonstop at all other times which isn't super good even with prodigious amounts of DoEvents.

I'd consider using the Windows Task Scheduler to perform a batch file taskkill, alongside another schedule to launch. I have a few workbooks that open themselves on Mondays, run SQL, and auto-email their self refreshed PivotTables and then self close.

Or even invoking the Form_Timer property of an empty Access Form which self runs at an interval you command. I use this type of construct for code I need to run very often (every 80 seconds in my case) but without the volatility of continuous processor burden.