Compare 20 refrigerants by GWP, ODP, ASHRAE safety class, and COP. Check EU F-Gas and EPA SNAP compliance. View replacement pathways for R-22, R-134a, and R-404A.
Filters
Max GWP
Evap. temp. T_e
°C
Cond. temp. T_c
°C
Replacement pathway
Compare two refrigerants
Results
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GWP (A)
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GWP (B)
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COP index (A)
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COP index (B)
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EU F-Gas (A)
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EU F-Gas (B)
Refrigerant
GWP
ODP
Safety
Boiling °C
COP index
F-Gas
GWP Comparison
GWP vs COP Scatter
Theory & Key Formulas
$COP_{Carnot}= \dfrac{T_e + 273.15}{T_c - T_e}$
The COP index normalises each refrigerant's cycle efficiency relative to R-22=100, incorporating molecular efficiency, compression ratio, and molecular weight via a semi-empirical factor.
What is Refrigerant Selection?
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What exactly is a refrigerant's "GWP" and why is it such a big deal now?
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Basically, GWP stands for Global Warming Potential. It's a number that compares how much heat a gas traps in the atmosphere compared to carbon dioxide (CO₂) over 100 years. In practice, a refrigerant with a GWP of 1,000 is 1,000 times worse for global warming than CO₂. Try moving the "Max GWP" slider in the simulator above to see how many common refrigerants get filtered out as you lower the limit.
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Wait, really? So if GWP is so important, why don't we just use the one with the lowest number? What's the catch?
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Great question! The catch is a three-way trade-off: efficiency, safety, and cost. A common case is R-290 (propane), which has a GWP of 3 but is highly flammable. Meanwhile, older refrigerants like R-404A are non-flammable but have a GWP over 3,900. The simulator's "Safety" column shows this classification. When you change the "Replacement pathway" parameter, you'll see how engineers balance these factors to find a suitable swap.
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Okay, that makes sense. But what about this "COP Index" in the table? How do the evaporation and condensation temperatures I set affect that?
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The COP (Coefficient of Performance) Index tells you how efficient the refrigerant's cycle is. It's normalized so R-22 = 100. The temperatures you set are crucial! For instance, in a supermarket freezer, T_e might be -10°C and T_c 40°C. The underlying physics is based on the Carnot cycle efficiency, which depends entirely on the temperature difference. A smaller difference (T_c - T_e) means a higher, more efficient COP. Play with the T_e and T_c sliders and watch the COP Index values change for each refrigerant.
Physical Model & Key Equations
The theoretical maximum efficiency for any refrigeration cycle is given by the Carnot COP. It depends solely on the absolute temperatures of the heat source (evaporator) and heat sink (condenser).
$$COP_{Carnot}= \dfrac{T_e + 273.15}{T_c - T_e}$$
Where $T_e$ is the evaporation temperature (°C), $T_c$ is the condensation temperature (°C), and 273.15 converts Celsius to Kelvin. The denominator $(T_c - T_e)$ is the temperature "lift" the compressor must overcome. A smaller lift means much higher efficiency.
Real refrigerants never achieve the Carnot COP. The simulator's "COP Index" normalizes a refrigerant's actual cycle efficiency against a baseline (R-22 = 100), incorporating molecular properties and real-world losses.
This index allows for quick comparison. A value of 110 means refrigerant X is about 10% more efficient than R-22 under the same T_e and T_c conditions you've set. This is critical for calculating energy costs and carbon footprint.
Real-World Applications
Supermarket Refrigeration: Large systems often used R-404A (GWP ~3940). Due to F-Gas regulations, they are now transitioning to lower-GWP blends like R-448A (GWP ~1270). The simulator's "Replacement pathway" filter helps identify these drop-in or retrofit alternatives while checking for efficiency gains or penalties.
Automotive Air Conditioning: The industry standard was R-134a (GWP ~1430). New models now use R-1234yf (GWP <1), which is mildly flammable but meets strict safety standards (A2L). This switch is directly driven by EU and US EPA SNAP regulations, which you can check in the simulator's compliance columns.
Residential Heat Pumps: For heating and cooling homes, R-410A (GWP ~2088) is being phased out. R-32 (GWP ~675) is becoming a mainstream alternative, offering higher efficiency (check its COP Index) and a lower GWP, though it is also classified as mildly flammable (A2L).
Industrial Chillers: Large-capacity chillers for buildings or processes are exploring "natural" refrigerants like Ammonia (R-717, GWP=0) or CO₂ (R-744, GWP=1). These have excellent efficiency but come with challenges in toxicity or high operating pressure, highlighted in the simulator's safety and property data.
Common Misconceptions and Points to Note
When starting to use this tool, there are several pitfalls that engineers, especially those with less field experience, often fall into. First is the idea that "a low GWP means everything is okay." While it is indeed the most critical metric for environmental regulation compliance, for example, CO2 (R-744) has a GWP=1 but requires system strength capable of handling its high operating pressure. You cannot simply reuse an existing R-404A compressor as-is. Second is "judging energy-saving performance based solely on the COP index." The tool's COP index is only a relative value under specific temperature conditions (Te, Tc). In actual equipment, heat exchanger size and compressor efficiency need optimization for each refrigerant, and performance rarely matches the tool's numbers exactly. For instance, while ammonia has a high COP, there are trade-offs, such as the inability to use copper piping, which changes system cost. The third point of caution is how to interpret safety classifications. When selecting a refrigerant other than A1 (non-flammable, non-toxic), regulations for the installation location are critical. For example, if using R-32 (A2L: mildly flammable) in an indoor unit, you must verify the manufacturer-specified ventilation requirements and space volume limitations. This tool is a starting point for "comparison"; detailed checks of manufacturer catalogs and Safety Data Sheets (SDS) are essential for final decisions.