I hear a noise coming from the serpentine belt area. Sounds like a bearing. I just put on a new belt and the noise is still there. The tensioner seems to be working fine. What could this be?

When in Park or Neutral does the noise change if you rev the engine? Whining noise generally come from a worn bearing so there will be a few things to check.
First check the serpentine belt. A loose or worn belt will cause noise. Carefully watch the belt with the engine at idle. Does it run smoothly or 'bounce' as it spins? Bouncing could suggest the spring in the belt tensioner is worn and has started to go slack.
Stand in front of the vehicle with the hood open and carefully listen to the engine. Sometimes you can hear if it is on one side of the engine or the other.
The most likely causes of the whine will be...
Power steering pump, A/C pump, Water pump, alternator pulley, belt tensioner and it's pulley or an idler pulley.
Parts like the alternator have more than one bearing in them so that could be another area to check. If the serpentine belt is off you can spin each pulley by hand. Listen and feel for a gritty growl as it spins. Bearings in good condition are usually smooth and quite.
Try this YouTube video. **NOTE** Be VERY CAREFUL if you try the tests in the video.

https://www.youtube.com/watch?v=JRHj9_pwx7o

The tensioner is an automatic device. You DONT Adjust it. Sounds like you need a new belt and probably should replace the tensioner. Tensioner have a limited lifespan usually 75000 to 100000 miles

the clutch and bearing assembly is failing it is a freewheeling pulley till clutch is engaged but it has bearings which can fail

That could be from a loose or cracked serpentine belt which might be caused by the spring loaded tensioner wearing out and not keeping the belt tight. Or it could be one of the pulleys having a bad bearing. If you take off the serpentine belt and turn each pulley you should be able to hear or feel which one it is.

The noise is coming from the belt tensioner or idler pulley, either one can make this noise. Do not put belt dressing on a serpentine belt.

It sounds like your water pump is going it usually vibrates throughout everything if it was your alternator it would show signs with your power the easiest way would to take your belt off remembering the belt route and spin the alternator pulley and the water pump pulley to see if they spin freely without noise

You might need a new belt, or the spring in the belt tensioner is weak and not holding the belt tight to the pulleys, in which case that will need replacing.

The serpentine belt area is large. Remove belt and spin the IDLER PULLY of the belt TENSIONER. and listen for a bearing noise. A common failure. Hope this helps

Yes there is a bearing in the AC clutch assembly, and the bearing can be changed with out swapping out for a whole new AC compressor unit or even taking the unit out. 
The other thing to you may want to check is the Serpentine belt tensioner. The tensioner then to break apart and or when the clutch activate put's more pressure on the system and the idler pully bearing could alsy be the problem. 
Spray some water on the fan belt whale the engine is running and see if the noise goes away and comes back as the water dry's. If the noise goes away then it's just a worn belt and need to be changed or you may want to do the quick fix and buy Fan belt dressing. 
Good luck and hope this helps

I'd remove the belt/belts and check all the idler pulleys. Did you retighten the belts or is it a single serpentine belt with an auto tensioner?