I want to know what is a fuction of a pressurization units in the Chilled water pump cicuit.

The pressurisation unit is a system which senses the pressure of the air inside the pressurization tank and based on the fluctuations the water in the ballons will get injected to the chilled water circuit, it will be accompanied with a expansion tank connected by a pump. Even the this will feed the necessary during the thermal expansion of the chilled water pipes or the flexible connections in the circuit.

Rather than having a expansion tank alone to cater the losses of the water in the system this is highly efficient by maintaining the pressure under the cut in and cut off tolerances.

Trust it clatifies