Background

The Past: CFCs

The Present: HCFCs & HFCs

The Future: ?

Information

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The Substitutes for CFCs

Two of the most popular proposed substitutes for chlorofluorocarbons are hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs). According to Environment Canada, like CFCs, they are used for refrigeration and air conditioning, foam blowing (the manufacture of foams), solvents and aerosols, health products (such as the metered dose inhaler), sterilization, and certain fire protection applications. While they have the benefits of CFCs, HCFCs and HFCs do not have the ozone-damaging effects of CFCs. The main advantage that HCFCs and HFCs have over CFCs is that they are much less stable and more reactive with their additional hydrogen atom(s), meaning they can usually break down in the troposphere before reaching the stratosphere and attacking the ozone. However, due to their disadvantages, it has been recommended (by the Standing Committee on Environment of Canada) that they are used only if: other safe alternatives are not available, the HCFCs and HFCs with the least ODP and GWP are used, and the usage amount is not too great.

HCFCs HFCs HCFCs and CFCs in Canada
 

HCFCs

Hydrochlorofluorocarbons are halocarbon compounds that contain hydrogen, chlorine, fluorine, and carbon atoms. They are like CFC molecules, except hydrogen atoms have replaced some chlorine atoms.

Advantages and Disadvantages of HCFCs
Advantages
Disadvantages
  • Replacement of the chlorine atom(s) with hydrogen atoms means that less chlorine atoms are released to the stratosphere --> ODP decreased
  • Extra hydrogen (H) dissipates almost all the chlorine in the troposphere before the chlorine can reach the ozone layer (the extra hydrogen makes them have a lower stability than CFCs) --> lower ODP than CFCs (only 2% - 10% of CFCs’)
  • Lower atmospheric lifetimes (2 - 25 years) than CFCs (100 years or more)
  • Low toxicity; no or low flammability; do not produce smog
  • Still contains chlorine that can attack the ozone layer
  • Can contribute to global warming (it’s a greenhouse gas)
  • More expensive to produce than CFCs











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    5 possible HCFC alternatives for CFC refrigerants are HCFC-22, HCFC-123, HCFC-124, HCFC-141b, and HCFC-142b.
    Their uses can be seen in the following table (Figure 3.1).

    Applications of HCFC Compounds
    HCFC Compound
    Refrigerants Applications
    Blowing Agents Applications
    Other Uses
    HCFC-22
    (CHClF2)
    Low temperature and medium temperature applications; household, commercial refrigeration and air conditioning applications. Component in ternary refrigerant blend.
    Polystyrene, polyethylene, polyurethane, polyisocyanurate, and phenolic
    Propellant.
    HCFC-123
    (CF3CHCl2)
    Chillers.
    Polyurethane, polystyrene, polyisocyanurate, and phenolic
    Component in cleaning agent blend.
    HCFC-124
    (CHClFCF3)
    Chillers. Component in ternary blend for medium temperature applications and automotive air conditioning service.
    Polystyrene, polyethylene, polyurethane, polyisocyanurate, and phenolic
     
    HCFC-141b
    (CH3CCl2F)
     
    Polyurethane, polyisocyanurate, and phenolic
    Component in cleaning agent blend
    HCFC-142b
    (CH3CClF2)
     
    Polystyrene, polyurethane, polyethylene, polyisocyanurate, and phenolic
    Propellant.

    Figure 3.1: Applications of HCFC Compounds
    (Source: Billy C. Langley, Refrigerant Management, p. 17)
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    Since HCFCs still have an ozone depletion potential (even though it is lower than CFCs’), they are considered to be acceptable replacements only for a while as a transitional plan.
     

    HFCs

    Hydrofluorocarbons are compounds that contain hydrogen, fluorine, and carbon atoms. They are like CFC molecules, except hydrogen atoms have replaced the chlorine atoms.

    Advantages and Disadvantages of HFCs
    Advantages
    Disadvantages
  • Do not contain chlorine --> no ozone depletion potential
  • Extra hydrogen (H) makes them have a lower stability than CFCs
  • Lower atmospheric lifetimes (2 - 25 years) than CFCs (100 years or more)
  • Low toxicity; no or low flammability; do not produce smog
  • Can contribute to global warming (it’s a greenhouse gas)
  • More expensive to produce than CFCs





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    4 possible HFC alternatives for CFC refrigerants are HFC-23, HFC-125, HFC-134a, and HFC-152a. Their uses can be seen in the following table (Figure 3.2).

    Applications of HFC Compounds
    HFC Compound
    Refrigerants Applications
    Blowing Agents Applications
    Other Uses
    HFC-23
    (CHF2)
    Possible low temperature alternative.
     
    Plasma etchant.
    HFC-125
    (CHF2CHF3)
    Blend component for low temperature and medium temperature applications.
     
     
    HFC-134a
    (CH2FCF3)
    Household and commercial refrigeration systems, automotive air conditioning. Medium temperature food cases and chillers.
    Polystyrene, polyurethane, polyisocyanurate, and phenolic
    Propellant for aerosol drugs/pharmaceuticals.
    HFC-152a
    (CH3CHF2)
    Component in ternary blend for medium temperature applications and automotive air conditioning service.
    Polystyrene, polyurethane, polyisocyanurate, and phenolic
    Propellant.

    Figure 3.2: Applications of HCFC Compounds
    (Source: Billy C. Langley, Refrigerant Management, p. 17)
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    Considering the great drawback of HCFCs of having ozone depletion potential, the usage of HFCs would be more ideal.
     

    HCFCs and HFCs in Canada

    This section gives a brief description on how Canada handles HCFCs and HFCs.

    Due to the undeniable fact that HCFCs still deplete the ozone, measures need to be taken. In Canada, the date of prohibition for consumption of HCFCs, except for HCFC-123, is Jan. 1, 2020. HCFC-123 will be prohibited on Jan. 1, 2030. Finally, the use of HCFCs in refrigeration and air-conditioning equipment up to 0.5% is allowed only up to 2030. This is all a part of Canada’s Phase-out Strategy (Figure 3.3) according to the Montreal Protocol in order to protect the ozone layer.

    Canada’s HCFC Phase-out Schedule
    Figure 3.3: Canada’s HCFC Phase-out Schedule
    (Source: Environment Canada, http://www.ec.gc.ca/ozone/EN/SandS/index.cfm?p=HCFC)

    The following chart (Figure 3.4) shows the controlled HCFC refrigerants in Canada.

    The Controlled HCFCs in Canada
    Figure 3.4: The Controlled HCFCs in Canada
    (Source: Environment Canada, http://www.ec.gc.ca/ozone/EN/SandS/index.cfm?p=HCFC)

    On the other hand, the next chart (Figure 3.5) shows the HFCs that are used as halocarbon alternatives in Canada.

    The HFCs Used as Alternatives in Canada
    Figure 3.5: The HFCs Used as Alternatives in Canada
    (Source: Environment Canada, http://www.ec.gc.ca/ozone/EN/SandS/index.cfm?p=HFC)

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