A QlikView reload reloads the data into your data model. During a reload your sheets and objects are not directly affected. When a user accesses the QVW the visual objects are evaluated based on the current data in the QVW file and then presented to the user.
There are options to do a partial reload to only refresh parts of your data model, or to use incremental reloads to only load the changes in data compared to previous reload. These are typically option to lok at if you have probelms with the current reload time.
Personally I would promote trying to use QlikView to look at the data, and do your data discovery. Exporting data kind of moves you away from the efficiency of discovery data in QlikView.
What is the reason that you want to reload only parts of your application?
What is the reason for exporting data to excel on every reload?
For more advanced and scheduled static reporting I would suggest that you look at QlikView NPrinting; Introducing QlikView NPrinting | Qlik