What type of system uses 40 X 2.5 to 3.5 ton connected to a single cooling tower.

Hello.

I am considering purchasing a new building but there was a strange configuration that I have not seen before in any of my other buildings.

Above the ceiling, they had about 40 individual 2.5 to 3.5 ton condensing units which has a single cooling tower(Marley) of the roof.

What type of system is this considered? Is this considered to be a more efficient way to do the air conditioner in a over 80,000 SQ FT building?

Thanks.