first of all are a date field or a flag field in your excel file which can be used to identify new records?
If YES do an initial load and save your table as a *.qvd file.
Find MaxDate as example and expand the load statement .....from ..... Where Date > $(MaxDate);
Now load your *.qvd file. QlikView concatenate the new records to the ones coming from your qvd.
Store the new *.qvd file. Get the new MaxDate and so on.
See also the attached application (comments are in german but i´m sure you will understand the logic).
QVDGenerator.qvw 132.2 K