Use Projectnumber instead of Projectname for naming of download zip-files
The projectname is a description of a project that does not has to be unique. The unique identifier for the project is the projectnumber. Use this (with timestamp) when creating zip files.
The projectnumber has an unique value, the Project name does not has to be unique
The downloaded zip files have the projectname and a timestamp for uniqueness. Using the project number instead would not add value.