As shown in the illustrated LP centrifugal...

As shown in the illustrated LP centrifugal...

Question 1 of 2921866636eee28f7522a1c51f32f

As shown in the illustrated LP centrifugal chiller pressure maintenance system, what is its functional purpose? Illustration RA-0040

Question 1 of 29218

Q

As shown in the illustrated LP centrifugal chiller pressure maintenance system, what is its functional purpose? Illustration RA-0040

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🔍 Key Concepts

• Note that this is a low-pressure centrifugal chiller that normally operates below atmospheric pressure on the refrigerant side • Focus on what a dedicated pressure maintenance system (with tank, heater, pump, check valve, and pressure controllers) would be trying to control when load is very low or the machine is stopped • Compare the functions of surge control in a centrifugal compressor versus air leakage prevention in a low-pressure (subatmospheric) system

💭 Think About

• When a low-pressure chiller is at very low load or idle, what happens to the internal refrigerant pressure relative to atmospheric pressure, and why is that important? • Look at the tank, heater, and pump in the illustration: are they arranged to move refrigerant for cooling, or to adjust system pressure to a safe range? • Which of the choices specifically addresses the problem created when part of the system pulls a deeper vacuum than intended?

✅ Before You Answer

• Identify whether the system shown is acting during low load and idle conditions or mainly during normal, full-load operation • Decide if a pressure maintenance system would primarily change compression ratio in the compressor, or instead limit how far below atmospheric pressure the machine can go • Ask which answer choice most directly addresses air entering a subatmospheric (vacuum) refrigerant circuit under the conditions shown in the illustration