ODP ODP Refrigeration Systems and Equipment 1

Question 1

Which type of refrigeration system is most commonly associated with large commercial buildings and was historically charged with CFC-11 or CFC-113?

Accepted Answer

Centrifugal chiller

Answer

Large centrifugal chillers used CFC-11 and CFC-113 as primary refrigerants, making them major contributors to ozone depletion and a key target of the Montreal Protocol.

Question 2

What characteristic of low-pressure CFC systems makes refrigerant recovery more challenging compared to high-pressure systems?

Accepted Answer

They operate below atmospheric pressure, requiring air purging and special recovery techniques

Answer

Low-pressure systems like CFC-11 chillers operate in a vacuum, so air infiltration is common and must be purged during recovery to prevent contamination.

Question 3

In HVAC/R systems, what is the purpose of an 'air purger' on a low-pressure centrifugal chiller?

Accepted Answer

To remove non-condensable gases like air and nitrogen that entered the system

Answer

Air purgers on low-pressure chillers remove non-condensable gases that infiltrate the below-atmospheric system, which would otherwise reduce efficiency and increase purge emissions.

Question 4

Which retrofit refrigerant was commonly approved to replace CFC-11 in existing low-pressure centrifugal chillers?

Accepted Answer

HCFC-123 (R-123)

Answer

HCFC-123 was the primary drop-in replacement for CFC-11 in centrifugal chillers due to its similar thermodynamic properties and lower (though not zero) ODP.

Question 5

What is the main reason CFC refrigerants were used extensively in large commercial refrigeration systems before the 1990s?

Accepted Answer

They were non-flammable, non-toxic, chemically stable, and had excellent thermodynamic properties

Answer

CFCs were ideal commercial refrigerants because they were chemically inert, non-flammable, low-toxicity, and had thermodynamic properties well-suited for a wide range of applications.

ODP - Ozone Layer Depletion Practice Test

ODP - Ozone Layer Depletion Practice Test

ODP ODP Refrigeration Systems and Equipment 1