VRF or a chiller plant, and how to choose
Tonnage tells you how much cooling a building needs. It does not tell you which system should deliver it. Here is how that second decision actually gets made.
Most buildings arrive at a number before they arrive at a system. The tonnage gets estimated, a figure gets quoted, and the question of what kind of plant is settled by whoever quoted first. It is worth slowing down at that point, because the two options behave very differently over twenty years.
Where VRF wins
VRF varies refrigerant flow to each indoor unit, so every zone holds its own set-point and the plant tracks part load closely. Buildings spend most of their hours well below peak, which is exactly where that matters.
It suits small to mid-sized buildings, phased fit-outs, and anywhere a plant room would be an expensive thing to find.
Where a chiller plant wins
Above roughly 100 TR the economics turn. A central plant is more efficient at sustained high load, it scales past what VRF can practically reach, and it gives you one place to maintain rather than dozens.
The trade is a plant room, pumps, and pipework, which is a design decision rather than an afterthought.
The question that actually decides it
Not tonnage. Ask how the building is used: how many hours it needs cooling, how independently the zones behave, and whether anyone will be there to maintain a plant room. A 60 TR office running eight hours a day and a 60 TR facility running continuously do not want the same answer.