Because of the enormous range of flows and pressures, the cooling system must be able to cool a few gas molecules per second as well as a gigantic number. This enormous variation in cooling capacity in combination with the fineness of the controls (stability 0.05 ^oC) is unique in the world.

Ammonia

Ammonia is the primary coolant. It evaporates on thin tubes through which the gas flows. The temperature at which evaporation takes place, that is the boiling point, is determined by the vapour pressure of the ammonia.

By adjusting the suction pressure of multiple compressors of varying capacities, the boiling point of the evaporating ammonia, and the amount that evaporates, can be regulated with very high precision. In turn, this results in a finely-adjustable cooling capacity over an extremely large range.