Refrigerators and freezers, as low-temperature storage equipment for household and commercial use, have seen continuous iterations in refrigerant selection centered around “refrigeration efficiency adaptability” and “environmental regulatory requirements”. The mainstream types and characteristics in different stages are highly aligned with the needs of the equipment.
Early mainstream: Application of CFCs refrigerants with “high efficiency but high harm”
From the 1950s to the 1990s, R12 (dichlorodifluoromethane) was the absolute mainstream refrigerant. In terms of equipment adaptability, the thermodynamic properties of R12 perfectly matched the needs of low-temperature storage – with a standard evaporation temperature of -29.8°C, it could easily meet the temperature requirements of refrigerator fresh-keeping compartments (0-8°C) and freezing compartments (below -18°C). Moreover, it had extremely strong chemical stability and excellent compatibility with the copper pipes, steel shells, and mineral lubricating oils inside refrigerators, rarely causing corrosion or pipe blockages, and could ensure the service life of the equipment for more than 10 years.
R12 has an ODP value of 1.0 (a benchmark for ozone-depleting potential) and a GWP value of approximately 8500, making it a strong greenhouse gas. With the entry into force of the Montreal Protocol, the global use of R12 in newly produced freezers has been gradually prohibited since 1996. Currently, only some old equipment still has residual such refrigerants, and faces the dilemma of no alternative sources during maintenance.
Transition stage: Limitations of “partial replacement” with HCFCs refrigerants
To bridge the phase-out of R12, R22 (difluoromonochloromethane) was once briefly used in some commercial freezers (such as small convenience store freezers). Its advantage lies in that its thermodynamic performance is close to that of R12, without the need for significant modifications to the freezer’s compressor and pipeline design, and its ODP value is reduced to 0.05, significantly weakening its ozone-depleting capacity.
However, the shortcomings of R22 are also obvious: on the one hand, its GWP value is about 1810, still belonging to high greenhouse gases, which does not conform to the long-term environmental protection trend; on the other hand, the refrigeration efficiency (COP) of R22 is lower than that of R12, which will lead to an increase in power consumption by about 10%-15% when used in household refrigerators, so it has not become the mainstream of household refrigerators. With the accelerated global phase-out of HCFCs refrigerants in 2020, R22 has basically withdrawn from application in the field of refrigerators and freezers.
I. Current mainstream refrigerants: Scenario-specific adaptation of HFCs and low-GWP types
Currently, the refrigerant selection for refrigerators in the market shows the characteristics of “differentiation between household and commercial use, and balance between environmental protection and cost”, mainly divided into two mainstream types, adapting to the functional needs of different equipment:
1.Small freezers: “Stable dominance” of refrigerants
R134a (tetrafluoroethane) is the most mainstream refrigerant for current refrigerators (especially models with a capacity of less than 200L), accounting for more than 70%. Its core adaptation advantages are reflected in three aspects: first, it meets environmental protection standards, with an ODP value of 0, completely eliminating the risk of ozone layer damage and complying with the basic requirements of global environmental regulations; second, its thermodynamic performance is suitable, with a standard evaporation temperature of -26.1°C, which, together with the high-efficiency compressor of the refrigerator, can stably achieve the temperature of the freezing compartment from -18°C to -25°C, and its refrigeration efficiency (COP) is 8%-12% higher than that of R22, which can reduce the power consumption of the equipment; third, it has reliable safety, belonging to class A1 refrigerants (non-toxic and non-flammable), even if a slight leakage occurs, it will not cause safety hazards to the family environment, and has good compatibility with the plastic parts and compressor lubricating oil inside the refrigerator, with a low failure rate.
In addition, some mid-to-high-end household refrigerators will use R600a (isobutane, a hydrocarbon) – a natural refrigerant, which has an ODP value of 0 and a GWP value of only 3, with far better environmental performance than R134a, and its refrigeration efficiency is 5%-10% higher than that of R134a, which can further reduce energy consumption. However, R600a belongs to class A3 refrigerants (highly flammable), and when its volume concentration in the air reaches 1.8%-8.4%, it will explode when exposed to an open flame. Therefore, it is only limited to use in household refrigerators (the charge amount is strictly limited to 50g-150g, much lower than that of commercial equipment), and the refrigerator needs to be equipped with anti-leakage detection devices (such as pressure sensors) and explosion-proof compressors, with a cost 15%-20% higher than that of R134a models, so it has not been fully popularized.
2.Commercial freezers / large refrigerators: “Gradual penetration” of low-GWP refrigerants
Commercial freezers (such as supermarket island freezers) have higher requirements for “environmental protection” and “refrigeration efficiency” of refrigerants due to their large capacity (usually more than 500L) and high refrigeration load. Currently, the mainstream choices are divided into two categories:
(1) HFCs mixtures: “High-load adaptation” of R404A
R404A (a mixture of pentafluoroethane, difluoromethane, and tetrafluoroethane) is the mainstream refrigerant for commercial low-temperature freezers (such as -40°C quick-freezing freezers), accounting for about 60%. Its advantage is that its refrigeration performance under low-temperature conditions is outstanding – at an evaporation temperature of -40°C, the refrigeration capacity is 25%-30% higher than that of R134a, which can quickly meet the low-temperature storage needs of freezers; and it belongs to class A1 refrigerants (non-toxic and non-flammable), with a charge amount of up to several kilograms (far exceeding that of household refrigerators), without worrying about flammability risks, adapting to the high-load operation of large freezers.
However, the environmental protection shortcomings of R404A have gradually become prominent. Its GWP value is as high as 3922, belonging to high greenhouse gases. Currently, the European Union and other regions have issued regulations to restrict its use (such as prohibiting the use of refrigerants with GWP>2500 in newly produced commercial freezers after 2022). Therefore, R404A is gradually being replaced by low-GWP refrigerants.
(2) Low-GWP types: “Environmental alternatives” of R290 and CO₂
Against the background of tightened environmental regulations, R290 (propane) and CO₂ (R744) have become emerging choices for commercial freezers, adapting to different needs in different scenarios:
R290 (propane): Mainly used in small commercial freezers (such as convenience store horizontal freezers). Its ODP value is 0, GWP value is about 3, with extremely strong environmental protection; and its refrigeration efficiency is 10%-15% higher than that of R404A, which can reduce the operating energy consumption of commercial freezers (commercial equipment operates for more than 20 hours a day, and energy consumption costs account for a high proportion). However, R290 belongs to class A3 refrigerants (highly flammable), and the charge amount needs to be strictly controlled within 200g (so it is only limited to small freezers). In addition, the freezer needs to adopt explosion-proof compressors, anti-leakage pipelines (such as copper-nickel alloy pipes) and ventilation and heat dissipation designs. Currently, its proportion in European convenience store freezers has exceeded 30%.
CO₂ (R744): Mainly used in ultra-low-temperature commercial freezers (such as -60°C biological sample freezers). Its standard evaporation temperature is -78.5°C, which can achieve ultra-low-temperature storage without a complex cascade refrigeration system; and it has an ODP value of 0 and a GWP value of 1, with irreplaceable environmental protection, and is non-toxic and non-flammable, with better safety than R290. However, CO₂ has a low critical temperature (31.1°C). When the ambient temperature exceeds 25°C, “transcritical cycle” technology is required, resulting in the compressor pressure of the freezer being as high as 10-12MPa, requiring the use of high-strength stainless steel pipelines and high-pressure-resistant compressors, with a cost 30%-40% higher than that of R404A freezers. Therefore, it is currently mainly used in scenarios with extremely high requirements for environmental protection and low temperatures (such as medical and scientific research freezers).
II. Future trends of refrigerants: Low GWP and high safety become core directions
Combined with global environmental regulations (such as the EU F-Gas Regulation, China’s Montreal Protocol implementation plan) and equipment technology upgrades, the refrigerants for refrigerators and freezers will show three major trends in the future:
Household refrigerators: R600a gradually replacing R134a – with the maturity of anti-leakage and explosion-proof technologies (such as new sealing strips, automatic leakage cut-off devices), the cost of R600a will gradually decrease (it is expected that the cost will drop by 30% in the next 5 years), and its advantages of high environmental protection and high refrigeration efficiency will be highlighted. It is expected that the proportion of R600a in household refrigerators will exceed 50% by 2030, replacing R134a as the mainstream.
Commercial freezers: “Dual-track development” of CO₂ and HFOs mixtures – for ultra-low-temperature commercial freezers (below -40°C), the technical maturity of CO₂ will continue to improve (such as high-efficiency transcritical cycle compressors), and the cost will gradually decrease, with the proportion expected to exceed 40% by 2028; for medium-temperature commercial freezers (-25°C to -18°C), R454C (a mixture of HFOs and HFCs, GWP≈466) will become the mainstream, with refrigeration performance close to that of R404A, and belonging to class A2L refrigerants (low toxicity and low flammability), with no strict restrictions on charge amount, balancing environmental protection and practicality.
Upgraded safety standards: From “passive protection” to “active monitoring” – regardless of household or commercial equipment, future refrigerant systems will generally be equipped with “intelligent leakage monitoring + automatic emergency treatment” functions (such as laser leakage sensors for household refrigerators, concentration alarms and ventilation linkage devices for commercial freezers), especially for flammable refrigerants such as R600a and R290, to eliminate potential safety hazards through technical means and promote the comprehensive popularization of low-GWP refrigerants.
III. Priority of core scenario matching
For the needs of different users, the following principles can be followed when selecting refrigerator refrigerants:
Household users: Priority is given to R600a models (balancing environmental protection and energy saving) – if the budget allows (200-500 yuan higher than R134a models), priority should be given to refrigerators marked with “R600a refrigerant”. Their power consumption is 8%-12% lower than that of R134a models, and they are more environmentally friendly; after purchase, attention should be paid to avoiding the back of the refrigerator (where the compressor is located) being close to open flames, and regularly checking the tightness of the door seals to reduce the risk of leakage.
Commercial users: Choose according to temperature needs (balancing cost and environmental protection) – medium-temperature freezers (such as convenience store freezers) can choose R290 models, with lower long-term operating energy consumption costs; for ultra-low-temperature freezers (such as quick-freezing equipment), if the budget is sufficient, CO₂ models are preferred, which are in line with the trend of environmental regulations and avoid the risk of phase-out in the future; if short-term cost sensitivity is a concern, R454C models can be chosen as a transition, balancing performance and environmental protection.
Maintenance and replacement: Strictly match the original refrigerant type – when maintaining old refrigerators and freezers, do not arbitrarily replace the refrigerant type (such as replacing R134a with R600a), because different refrigerants have different requirements for compressor lubricating oil and pipeline pressure. Mixed use will cause compressor damage or refrigeration failure. It is necessary to contact professionals to add refrigerants according to the type marked on the equipment nameplate.
Post time: Aug-29-2025 Views: