Refrigerators play a significant role in our daily lives and also in specialized fields like laboratories, pharmaceuticals, and research facilities. Refrigerant gas is the most essential component of a refrigerator which is responsible for absorbing heat and keeping things cool. Over the decades, the gases used in refrigerators have evolved significantly due to concerns about safety, energy efficiency and environmental impact such as global warming and ozone depletion.
In this blog, we'll explore the different types of refrigerant gases, how they have evolved, their performance characteristics, how to choose the best refrigerator and which refrigerants are commonly used in Labotemp refrigerators.
What is a Refrigerant Gas?
A refrigerant gas is a special fluid that is used in the cooling cycle of refrigerators and freezers. Refrigerant gas circulates inside the refrigerator system. Its main work is to absorb heat from the inside chamber and release it outside through a continuous cycle of evaporation and condensation.
Image: Refrigeration Cycle
Refrigerators don't create cold but they move heat from inside the refrigerator which is done by a continuous cycle of evaporation and condensation of a special gas called refrigerant. This refrigerant changes between liquid and gas, carrying heat from the inside of the fridge to the outside.
The cycle of refrigeration starts in the compressor which is the heart of the system. The compressor takes the low-pressure refrigerant gas and squeezes it which in turn increases the pressure and temperature of the refrigerant gas. The hot and high-pressure gas then travels to the condenser coils which is usually on the back of the refrigerator. It releases its heat into the cooler surrounding air through this condenser coil which causes the refrigerant to cool down and condense into a liquid.
The liquid then goes through the expansion valve which is a tiny opening that causes a sudden drop in pressure. This pressure drop makes the refrigerant expand and become extremely cold. Now this chilly mixture of liquid and gas enters the evaporator coils which are inside the fridge.
As the cold refrigerant flows through these coils, it absorbs heat from the food and air inside the refrigerator which causes it to evaporate and turn back into a low-pressure gas. This is the stage that makes refrigerator cold from inside. Then this low-pressure, warm gas is then sent back to the compressor to restart the cycle. This continuous process of compressing, condensing, expanding, and evaporating is what keeps the refrigerator cool by constantly pumping heat out of the fridge
The history of refrigerants reflects a journey toward safer and greener cooling:
Ammonia (R-717) and Sulfur Dioxide were used widely. While they were effective at cooling, they were toxic or hazardous which made them unsafe for household refrigerators. These natural refrigerants had excellent thermodynamic properties but they also required strong safety systems.
Chlorofluorocarbons (CFCs like R-12) became very popular because they were stable, non-toxic and efficient in use. Unfortunately it was later found that CFCs cause severe ozone layer depletion. The Montreal Protocol (1987) was established to save the ozone layer, ratified the elimination of ozone-depleting substances.
Hydrochlorofluorocarbons (R-22) and Hydrofluorocarbons (R-134a, R-410A) replaced CFCs. They solved the ozone issue but they contributed to global warming due to their high GWP(Global Warming Potential) values (R-134a: ~1,430 GWP and R-410A: ~2,088 GWP).
Now with the focus on sustainability refrigerants like R-600a (Isobutane), R-290 (Propane) and R-744 (CO₂) have become popular. These have low GWP (~3 for R-600a), zero ODP and they are also energy efficient. The main challenge with these gases is their flammability, but with proper system design and leak detection systems they are safe and reliable.
Hydrofluoroolefins (like R-1234yf, R-1234ze) are fourth-generation synthetic refrigerants composed of hydrogen, fluorine, and carbon, designed with ultra-low GWP (<1) and eco-friendly characteristics which make them a promising alternative for various applications.
Source: California Air Resources Board
Detailed Refrigerant Types:
Refrigerants are the working fluids and main components of the refrigeration cycle that make the cooling of refrigerators possible. The evolution of refrigeration gases reflects the refrigeration industry’s push for safety, efficiency, and sustainability. Here’s a closer look at the main types of gases used in refrigeration:
1. Ammonia (R-717)
Widely used in industrial refrigeration and large-scale food processing.
They have Zero ozone depletion potential (ODP), and also zero global warming potential (GWP) and are also very energy efficient.
They are Excellent for ultra-low temperature applications (-60°C to 0°C).
Toxic in high concentrations and requires strict safety protocols and trained technicians.
2. CFCs (e.g., R-12)
They were once most common in domestic refrigerators and automotive AC systems.
Now completely banned under the Montreal Protocol due to severe ozone damage.
Still present in older equipment, requiring careful recovery and disposal.
3. HCFCs (e.g., R-22)
They are considered transitional refrigerants which were less harmful than CFCs but still ozone-depleting.
Formerly they were dominant in air conditioning systems.
HCFCs were later phased out in developed countries since 2020 through the Montreal protocol, the global phase-out of HCFCs is still ongoing.
4. HFCs (e.g., R-134a, R-410A, R-404A, R-507)
High GWP makes them unsustainable in the long term; the phasedown of HFCs is mandated by the Kigali Amendment to the Montreal Protocol in 2016.
5. Hydrocarbons (R-600a, R-290, R-1270)
R-600a (Isobutane): Leading choice for domestic, laboratory refrigerators.
R-290 (Propane): Used in heat pumps and commercial systems.
R-1270 (Propylene): Increasingly applied in industrial settings.
Highly efficient and eco-friendly but flammable (A3 safety class) and it requires specialized handling.
6. Carbon Dioxide (R-744)
It's a natural refrigerant with zero ODP and a GWP of 1.
It operates at very high pressures which is well-suited for hot climates.
The gas is Non-toxic and non-flammable but requires advanced system design.
7. HFOs (e.g., R-1234yf, R-1234ze)
HFOs are next-generation synthetic refrigerants with ultra-low GWP (<1).
It has zero ODP and is considered a long-term replacement for HFCs.
It is already adopted in the automotive industry and it is expanding into commercial and industrial applications.
From ozone-depleting CFCs to climate-friendly natural refrigerants and HFOs, the refrigerant impact has undergone an important transformation. There is no doubt about refrigeration's future which will be safer, more effective and environmentally friendly solutions that support international sustainability objectives.
Yes, most refrigerant gases are harmful to both humans and the environment in some way or other but the answer depends on which type of refrigerant you are using and how it's handled. Let's break down the different types and their impact on the environment.
Older refrigerants like CFCs (such as R-12) and HCFCs (such as R-22) were once the most common and the industry standard. While they worked well for cooling they caused serious environmental damage:
CFCs are completely banned - These gases seriously damaged the ozone layer and were phased out under the Montreal Protocol in 1987.
HCFCs are being phased out - New production and import of most HCFCs were phased out as of 2020 in developed countries.
Today's common refrigerants like HFCs (R-134a, R-410A) solved the problem of ozone depletion but created a new one:
They don't damage the ozone layer
But they have high Global Warming Potential (GWP), which means they contribute significantly to climate change when released in the atmosphere
Natural refrigerants offer the best environmental profile:
Ammonia (R-717): Has zero ozone depletion potential and it doesn't contribute to global warming, but it is toxic to humans and also requires proper handling.
Carbon dioxide (R-744): Has no harmful effect on the ozone layer with ODP of 0 and GWP values of 1, which means it is better than many refrigerants in terms of Global Warming Potential.
Hydrocarbons (R-600a, R-290): Have zero global warming impact and don't deplete the ozone layer.
So in conclusion, refrigerant gases can be harmful but it depends on what type of refrigerant you are using. The refrigeration sector is currently making a coordinated attempt to switch to less harmful options. At Labotemp Scientific, we mostly use hydrocarbon-based refrigerants such as R-600a, R-290, and others.
Choosing the best refrigerant involves balancing several key factors such as environmental impact, safety, performance efficiency, cost, and many more as there's no single "perfect" option.
Environmental Impact: This is the most crucial consideration today as the world is moving towards an environmentally friendly future. Refrigerants are mostly rated on two main metrics ODP and GWP:
Ozone Depletion Potential (ODP): This Measures how much a refrigerant can harm the Earth's ozone layer. The goal is to choose a refrigerant with an ODP of zero.
Global Warming Potential (GWP): This Measures how much a refrigerant contributes to the greenhouse effect compared to carbon dioxide. Lower GWP values are better for the environment.
Safety: Refrigerants are classified based on their flammability and toxicity. An ideal refrigerant should be non-flammable and non-toxic especially when using for household appliances. However, many newer environmentally friendly refrigerants (like R-290, or propane) are highly flammable, which requires specialized equipment and handling.
Performance and Efficiency: A good refrigerant should have a high cooling capacity and be energy-efficient. It must also have the right thermodynamic properties to work effectively within the specific system's design. For example, a refrigerant's boiling point and pressure characteristics must match the operating conditions of the compressor and coils.
Cost and Availability: The refrigerant must be affordable and readily available for the lifetime of the equipment. Older refrigerants that are being phased out may become expensive or hard to find.
Compatibility: The refrigerant must be compatible with the system's components such as the lubricating oil, seals and piping. Using an incompatible refrigerant can damage the equipment.
Refrigerant gases have advanced significantly in a few decades, from harmful gases like CFCs, HCFCs to environmentally friendly gases like Hydrocarbons R-600a (Isobutane) and R-290 (Propane) to HFOs (Hydrofluoroolefins) which are environmentally friendly and also non-flammable. The desire for safer, more environmentally friendly and more effective refrigeration has pushed each stage of development.
Whether you're selecting equipment for a laboratory, pharmaceutical facility or any critical application, understanding refrigerant technology helps you make informed decisions that benefit both your operations and the environment. The decisions that are made today by the industries and countries around the world will determine both the long-term operational expenses and the effects on the environment.
Labotemp Scientific specializes in advanced, reliable refrigerators and freezers tailored to meet the needs of healthcare professionals worldwide.
