• SkillCat Team

Non-Ozone Depleting Refrigerants

Updated: 2 days ago

EPA 608 Core Chapter 17 (Take full course for free)


In this module, we will delve further into different types of non-ozone depleting refrigerants. Skip to quiz!


1. HFC Refrigerants


HFCs were developed as an alternative to CFCs and HCFCs. It was effective as a refrigerant and did not contain chlorine, so it did not destroy ozone.


But it turned out that while HFCs do not deplete the ozone layer, they contribute to global warming. We will go into specifics of global warming later in this module.


HFCs are a category of refrigerants called hydrofluorocarbons. R-32, R-125, and R134a are all examples of HFC refrigerants.


HFCs are made of


- Hydrogen

- Fluorine

- Carbon


2. HFO Refrigerants


As we discussed in Key Regulations, CFCs have been phased out, and HCFCs will soon be phased out. HFCs are also in the process of being phased out because of their high global warming potential.


Then there’s HFOs, which are a new class of refrigerants. HFOs have much lower global warming potential than HFCs.


HFOs are a category of refrigerants called hydrofluoroolefins. The HFO refrigerant we see most commonly is R-1234yf.

HFOs are composed of:

- Hydrogen

- Fluorine

- Carbon


Notice that the elements that HFOs are made of do not directly correspond to the letters in its name, like it has with other refrigerants. Notice also, that HFOs have the same elements as HFCs.


With HFOs, we have to beware that they are not compatible with silicone. Silicone elastomers are used in seals and gaskets in refrigeration systems. But in the presence of HFOs, silicone elastomers swell, so this affects how the system behaves.


Notice that HFOs do not contain chlorine, so they do not destroy ozone. Compared to HFCs, they are not as harmful in contributing to global warming.


3. Natural Refrigerants


Different types of refrigerants were developed in order to provide an alternative to the ozone depleting and global warming refrigerants. These alternatives to traditional refrigerants are called natural refrigerants.


These alternatives are called natural refrigerants because they can be found in nature and are generally much more environmentally friendly than past refrigerants.

Examples of natural refrigerants include:

- HCs, or hydrocarbons

- Carbon dioxide

- Ammonia


Examples of hydrocarbons are:

- Propane, which is known as either R-290, or HC-290

- Isobutane, which is known as either R-600a, or HC-600a


Note that propane is used for grilling, because it is highly flammable, so it is great for starting a fire. However, the propane used for grilling cannot be used to charge refrigeration systems.


Propane cylinders used for grilling are not rated for refrigerant use. This is because these propane cylinders contain impurities that can damage refrigeration equipment. Propane used for refrigeration purposes will be labeled R-290.


Carbon dioxide can also be used as a refrigerant. As a refrigerant, it is known as R-744.


Ammonia as a refrigerant is known as R-717. It has been used since the 1850s for cooling purposes. We see ammonia today mostly in commercial applications.


4. Conclusion


In this module, we discussed the non-ozone depleting refrigerants which were developed as an alternative to CFCs and HCFCs, as they were harmful to the ozone layer.


Question #1: HFCs are

  1. Hydrofluorocarbons

  2. Hydrochlorofluorocarbons

  3. Hydrocarbons

  4. Hydroflouridecarbons

Scroll down for the answer...











HFCs are hydrofluorocarbons.


Question #2: HFCs contain which of the following? (Select all that apply)

  1. Helium

  2. Hydrogen

  3. Halon

  4. Chlorine

Scroll down for the answer...











HFCs do not contain chlorine. Recall that chlorine destroys ozone and that HFCs were developed as an alternative to ozone-depleting CFCs and HCFCs. The H in HFC stands for Hydrogen


Question #3: HFCs contain which of the following? (Select all that apply)

  1. Fluorine

  2. Carbon

  3. Cadmium

  4. Chlorine

Scroll down for the answer...











Of the letters in HFC:


The H is for Hydrogen.

The F is for Fluorine.

And the last C is for Carbon.


Question #4: Which of the following are HFCs? (Select all that apply)

  1. R-134a

  2. R-32

  3. R-12

  4. R-22

Scroll down for the answer...











R-134a and R-32 are both HFC refrigerants.


Question #5: HFCs contain which of the following? (Select all that apply)

  1. R-01

  2. R-203

  3. R-125

  4. R-22

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R-125 is an HFC refrigerant.


Question #6: HFOs are

  1. Hydrofluorocarbons

  2. Hydrofluorooxygens

  3. Hydrocarbons

  4. Hydrofluoroolefins

Scroll down for the answer...











HFOs are hydrofluoroolefins.


Question #7: HFOs contain which of the following? (Select all that apply)

  1. Hydrogen

  2. Halon

  3. Chlorine

  4. Oxygen

Scroll down for the answer...











The H in HFO stands for hydrogen. The O does not stand for oxygen.


Question #8: HFOs contain which of the following? (Select all that apply)

  1. Fluorine

  2. Falon

  3. Oxygen

  4. Carbon

Scroll down for the answer...











The H in HFO stands for hydrogen.

The F stands for Fluorine.

The last element of HFOs is carbon, just like HFCs. The O does not tell you the name of an element in HFOs.


Question #9: Which of the following are HFOs? (Select all that apply)

  1. R-134a

  2. R-1234yf

  3. R-11

  4. R-22

Scroll down for the answer...











R-1234yf is an HFO refrigerant.


Question #10: Which of the following natural refrigerants? (Select all that apply)

  1. R-600a

  2. HC-600a

  3. R-134a

  4. R-22

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R-600a and HC-600a are both names for isobutane, which is a hydrocarbon refrigerant.


Question #11: Which of the following natural refrigerants? (Select all that apply)

  1. R-717

  2. R-744

  3. R-130

  4. R-290

Scroll down for the answer...











R-717 is ammonia.

R-744 is carbon dioxide.

R-290 is propane, a hydrocarbon refrigerant.

These three listed are all natural refrigerants.


Question #12: R-410a is the same as

  1. CFC-410b

  2. HFC-410b

  3. HFC-410a

  4. HFO-410a

Scroll down for the answer...











R-410a is an HFC.

So it is the same as HFC-410a.

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