Hello
1. Is System Copy and System Refresh are same task? If NO, then what is the difference?
There is no difference.
2. We have production server situated far away from quality server. So, what is the best possible way to move production server database (115 GB) backup?
115 GB is a very small database. You can use backup and restore method.
As you have Java stack you will need to do an export and import of the Java stack
http://scn.sap.com/docs/DOC-8324
https://websmp108.sap-ag.de/erp-inst
You can find the guide here under Installation section
Regards
RB