Wow!  Neat!!  What you have found are mud dauber wasp nests.  These are solitary wasps that don't build large paper colonies or hives.  What they do is create mud galleries, like you see there.  They then sting and paralyze large numbers of spiders, which they stuff into the galleries.  After the galleries are nearly filled, the female will lay an egg at the top of each.  When the wasp larva hatches out (that's the white, grub-like thing you see in the 2nd picture), it has all these paralyzed spiders to feed on.  About the time it runs out of spiders, it's time to pupate and then emerge as an adult wasp.

Nature is pretty neat.  Gruesome...but neat!

I try to leave these alone when I find them on the side of my yard barn or in the garage, but I don't see how you could have taken care of your air conditioner and kept these things alive. 

Please let us know if you have any other questions.