1 Refrigerant Types and Properties Free Online FlashCards

How does a refrigerant transfer heat?

A refrigerant absorbs heat as it evaporates and releases heat as it condenses.

What are two environmental concerns associated with CFCs?

CFCs can deplete stratospheric ozone and persist as greenhouse gases. They have been phased out of new production in many uses.

What is R-22, and where has it been used?

R-22 is an HCFC used in older residential and commercial air conditioners and heat pumps. HCFCs deplete ozone, generally less than CFCs.

What is a key environmental trade-off of HFCs?

HFCs have zero ozone-depletion potential, but many have high global-warming potential. R-410A and R-404A are examples.

What environmental and safety traits are common among HFOs and newer blends?

HFOs and many HFC/HFO blends typically have much lower global-warming potential than older HFCs and zero ozone-depletion potential. Some are mildly flammable.

What is the main safety hazard of hydrocarbon refrigerants?

R-600a (isobutane) and R-290 (propane) have very low global-warming potential and zero ozone-depletion potential, but are highly flammable (A3).

What important trade-off applies to R-744 (carbon dioxide)?

R-744 has a global-warming potential of 1, but many CO₂ systems operate at very high pressures.

What benefits and hazards characterize ammonia as a refrigerant?

Ammonia has excellent heat-transfer properties and no ozone-depletion potential, but it is toxic at hazardous concentrations and classified B2L.

What does the letter in an ASHRAE refrigerant safety group indicate?

In ASHRAE safety groups, A denotes the lower-toxicity class and B the higher-toxicity class.

What do the flammability classes 1, 2, and 3 indicate?

Class 1 refrigerants do not propagate a flame under the standard test; Class 2 indicates lower flammability, and Class 3 higher flammability.

What does the 2L designation mean?

The 2L designation identifies a lower-flammability refrigerant with low burning velocity.

Why is refrigerant pressure not a single fixed family value?

Pressure depends on the refrigerant’s temperature and condition; it is not one fixed value for an entire refrigerant family.