ODP ODP Refrigeration Systems and Equipment

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

Reciprocating compressor system

Answer

Window air conditioner

Answer

Absorption refrigeration unit

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

They use very large refrigerant charges that take longer to recover

Answer

Their refrigerant is flammable and requires explosion-proof equipment

Answer

They use mixed refrigerants that are difficult to separate

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

To purge refrigerant from the system before service

Answer

To remove moisture from the refrigerant charge

Answer

To regulate compressor suction pressure

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

HFC-134a (R-134a)

Answer

R-410A

Answer

R-404A

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

They were the only refrigerants available at the time

Answer

They were mandated by early EPA regulations

Answer

They had the lowest global warming potential of all available options

Question 6

Which supermarket refrigeration system configuration contributed most to CFC/HCFC emissions due to its long piping runs and multiple leak points?

Accepted Answer

Direct expansion (DX) rack system with remote cases

Answer

Self-contained display case units

Answer

Secondary loop refrigeration system

Answer

Absorption refrigeration system