I have a large closet that is windowless and I have computers in the room... I need to keep the room cooled and wanted to find an air conditioner that might help me achieve this... any suggestions?

Since an air conditioner removes heat from the air, it needs a way to vent this heat to the outside. Without venting the A/C unit will blow cold from one side and hot from the other, resulting in net cooling of zero.

There are allot of mini-split systems, but these are installed, not portable.

As mentioned above, air conditioners of all type suck in room temperature air, pass it over an evaporator coil, where it gets very cold, and puts it back into the room. However, in order for the air to get cold, concentrated heat needs to be forced out through the condenser fan outside.

Your best bet is to get a mini split system (one with separate condenser and air handler units) and permanently install it, since they are not portable.

Under cut the door on the closet, instal a bathroom exhaust fan in the ceiling and let it remove the heat from the room.

Mini split will do

I think that if you ut a portable air conditioning you will have to drill a hole in the wall for it to vent out

Put I mean