GWP (Global Warming Potential) is a measure of the contribution of a given gas to global warming compared to carbon dioxide (CO₂). The reference value for carbon dioxide is always 1, while the GWP values for other gases use this as a baseline.
How is GWP measured?
GWP takes into account the heat-trapping capacity of a gas and its atmospheric residence time. The calculation examines how much of a gas's global warming impact it has over a certain period of time (such as 20, 100 or 500 years) compared to CO₂.
Example:
If a gas has a GWP of 1000, it means that the gas contributes 1000 times more to global warming than the same amount of carbon dioxide over the same period of time.
GWP and refrigerants
GWP plays a key role in the classification of refrigerants, as these substances can be significant greenhouse gases.
CFCs (Chlorinated Fluorocarbons): Very high GWP values (between 5,000 and 10,000). Their use has now almost completely ceased due to their harmful effects on the ozone layer and climate change.
HCFCs (hydrochlorofluorocarbons): They have a lower GWP than CFCs (between 1000 and 4000). They are being phased out as they still have a significant environmental impact.
HFCs (hydrofluorocarbons): Widely used refrigerants, but their GWP value remains high (between 150 and 4000).
HFOs (hydrofluoroolefins): The new generation of synthetic refrigerants with low GWP values (usually below 20).
Natural refrigerants:
- CO₂ (R744): GWP value 1 (carbon dioxide).
- Ammonia (R717): GWP close to 0.
- Propane (R290): GWP is approximately 3.
- Comparison of GWP types
- Refrigerant type Example GWP value Note
- CFCs R12 8500 High environmental impact, phased out.
- HCFCs R22 1800 Phased out.
- HFCs R410a 2088 Under regulation, in the process of being replaced.
- HFOs R1234yf <1 Low GWP, new generation refrigerant.
- Natural gases CO₂, Ammonia 1 or close to 0 Environmentally friendly alternative.
Why is GWP important?
Environmental protection: Using materials with lower GWP values reduces the impact on climate change.
Regulatory requirements: The EU F-gas regulation and the Kigali Amendment restrict the use of high GWP refrigerants.
Sustainability: Low GWP refrigerants encourage the use of sustainable technologies.
Summary
GWP is a key metric in assessing the environmental impact of refrigerants and other greenhouse gases. The use of low-GWP materials helps mitigate global warming and promote sustainable technologies. Industries and regulators should pay special attention to introducing alternatives and increasing energy efficiency to protect the environment.