So that you get correct answer.
Do you mean you'll like to save the qvw file or save the data as QVD whenever the qvw file is run?
If you want the qvw file save whenever it reloads then,
ctlr + alt + U (User Preferences) then select Save tab, check Save Before Reload box.
If you want to save the data during reload then you have to use STORE command in your script.
STORE Table_Name INTO FileLocationPath
It's every important to clarify your question.
Hope this helps