ITUNES copying playlists from external back to windows 7 reducing size from lossless

I have a very large music library mostly in lossless taking up 500 GB on my external hard drive. I have now created 30 different playlists (above average songs) that I want to send back to my windows 7 PC in a lower quality. any ideas on the best way to accomplish this?

I know that I can change my library to look at my pc instead of my external drive, but I want only the playlist songs. I am worried that my external hard drive is going to crash because when I shuffle all songs for hours at a time the drive is working hard and getting hot. This movement back to PC should solve this and my external will stay as the pure storage and back up of my non playlist songs. Am I making sense?

Please help. I have searched and searched and can't find an answer.

Thanks

cjunemann