Global Warming Potential (GWP) of refrigerants is measured by comparing their heat-trapping ability over 100 years to that of CO2, using standardized testing methods.
Global Warming Potential (GWP) is a critical metric for evaluating the climate impact of refrigerants. It compares the heat-trapping ability of greenhouse gases to carbon dioxide (CO2) over a specific time frame, typically 100 years. Understanding GWP helps industries choose environmentally responsible refrigerants and comply with regulations.
What Is Global Warming Potential (GWP)?
GWP measures how much heat a greenhouse gas traps in the atmosphere compared to CO2. CO2 is the baseline with a GWP of 1. Refrigerants often have GWPs thousands of times higher, making their environmental impact significant if leaked.
How GWP Is Calculated
GWP depends on three factors:
- Radiative Efficiency: How effectively the gas absorbs infrared radiation.
- Atmospheric Lifetime: How long the gas remains in the atmosphere before breaking down.
- Time Horizon: The period over which the impact is measured (20, 100, or 500 years).
The most common reference period is 100 years, used by regulators like the California Air Resources Board (CARB).
Examples of High-GWP Refrigerants
| Refrigerant | 100-Year GWP | Comparison to CO2 |
|---|---|---|
| R-22 (HCFC) | 1,810 | 1,810x more potent |
| R-404A (HFC) | 3,922 | 3,922x more potent |
| R-410A (HFC) | 2,088 | 2,088x more potent |
Why High-GWP Refrigerants Are a Problem
Refrigerants with high GWP contribute significantly to climate change when leaked. For example:
- A 30-lb tank of R-22 has the same warming effect as driving 7 extra cars for a year.
- R-404A, a common supermarket refrigerant, is twice as potent as R-22.
Leakage rates in refrigeration systems can exceed 20% annually, making proper containment and recovery essential.
Regulations Phasing Out High-GWP Refrigerants
Governments worldwide are restricting high-GWP refrigerants under agreements like the Kigali Amendment. The EU and U.S. EPA have identified R-404A and R-507A for phase-out due to their extreme GWP values.
Low-GWP Alternatives
Newer refrigerants, such as hydrofluoroolefins (HFOs), have much lower GWPs:
- R-1234yf (HFO): GWP of 4
- R-32 (HFC): GWP of 675 (lower than R-410A)
Natural refrigerants like ammonia (R-717) and CO2 (R-744) have negligible or low GWPs, making them sustainable choices.
Best Practices for Reducing Refrigerant Emissions
To minimize environmental impact:
- Leak Prevention: Use welded joints and regular inspections.
- Proper Recovery: Ensure refrigerants are reclaimed at end-of-life.
- System Design: Opt for low-charge systems to reduce leakage risk.
For more on efficient heating solutions, see our guide on the best built-in gas heaters or electric heaters resembling wood stoves.
Future of Refrigerants
The HVAC industry is shifting toward ultra-low-GWP refrigerants. Innovations like magnetic cooling and solid-state refrigeration could eliminate refrigerant emissions entirely.
By understanding GWP, businesses can make informed choices that align with global climate goals.
