Regarding cooling on External Hard Drives

So I bought a 3.5' Comstar 500GB External Hard Drive to help with transferring my files from my old pc to my new one, and I'd like to use the EHD as much as my 500GB HDD in my pc. I'd use the EHD for music, videos, and files that don't take a lot of system resources like games. The problem is that I've noticed it getting pretty hot after about 2 hours of being plugged in to my computer.

My question is, as the title implies, "Is it safe to keep an EHD connected and powered on for the whole day? I turn my pc on in the morning, and off late at night, would overheating be a constant issue? I have the EHD standing upright on its stand, away from other devices so it can cool itself easier.

Many thanks in advance!