Frequently Asked Questions about Hydrocarbons
Please go over the categories below to find the answers to your questions.
Hydrocarbon refrigerants are environmentally friendly, non-toxic, non-ozone-depleting substitutes for chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), hydrofluoeoolefins (HFOs) and HFO blends.
What are their main advantages?
Hydrocarbons are one of the most climate-friendly and cost-efficient refrigerants for heating, cooling and freezing:
- Non-ozone depleting: Ozone Depletion Potential = 0
- Not climate damaging: Global Warming Potential for most HCs is below 1
- Non-toxic
- Safe: with proper handling
- Energy-efficient: usually better energy efficiency than CFC or HFC systems
- Cost-efficient: low refrigerant purchase price as well as lower system running costs
The following hydrocarbons can be used as a refrigerant in cooling & heating applications:
- R170 - ETHANE - C2H6
- R290 - PROPANE (Dimethylmethane) - C3H8
- R600 - BUTANE (N-Butane, Butane) - C4H10
- R600a - ISOBUTANE (2-Methylpropane) - C4H10
- R1270 - PROPYLENE (Propene) - C3H6
- R1150 - ETHYLENE - C2H4
However, the most commonly used hydrocarbon refrigerants are propane (mainly in commercial and industrial refrigerators and freezers, air conditioning and heat pumps), and isobutane (in domestic refrigerators and freezers).
Hydrocarbons are one of the most climate-friendly and cost-efficient refrigerants for cooling, freezing and heating:
- Non-ozone depleting: Ozone Depletion Potential = 0
- Not climate damaging: Global Warming Potential for most hydrocarbons is below 1
- Non-toxic
- Safe: with proper handling
- Energy efficient: usually better energy efficiency than CFC or HFC systems
- Cost efficient: low refrigerant purchase price as well as lower system running costs
Yes, with proper handling. Since hydrocarbons are flammable, some basic safety rules, which may differ slightly depending on the application, need to be respected by manufacturers, installers and users. As long as these rules are respected, it is perfectly safe to use hydrocarbons as refrigerants. Propane, for example, is used universally for heating and cooking. Hydrocarbons’ safe handling practices are well understood and practiced by the general global population. This makes them an appropriate alternative to climate-damaging chemical refrigerants, also in developing countries.
Yes. However, adhering to the safety guidelines that exist for any application using flammable refrigerants, the risks of using hydrocarbons can be kept to a minimum, thereby avoiding any threat to human health and safety. Many of the hydrocarbon- employing components used for commercial refrigerated appliances already meet safety standard requirements.
No. Hydrocarbons are not toxic for human beings and other living organisms.
No. Hydrocarbons do not contribute in any way to the depletion of the ozone layer.
No. Most hydrocarbons used as refrigerants have a 100-year Global Warming Potential (GWP) of below 1, meaning that they don’t pose a threat to the earth’s climate. By contrast, R404a, one of the chemical refrigerants hydrocarbons can replace, has a 100-year GWP of 4,200. To demonstrate this figure: over 100 years, 1 kg of released R404A heats the atmosphere at a rate equal to more than 4.2 metric tons of propane or isobutane!
There are two factors involved: Firstly, using hydrocarbons reduces the Direct greenhouse gas (GHG) emissions. This is due to HCs’ low Global Warming Potential (GWP) of less than 1, compared to a GWP of 1,360 for R134a, and even higher values for other chemical refrigerants. Why is this important? For example, from a typical supermarket refrigeration system, up to 25% of the total refrigerant charge is emitted to the atmosphere every year. Even assuming that leakage rates are the same (and R290 in self-contained cabinets have a very low leak rate), hydrocarbons, compared to any other chemical refrigerant currently used, will spare the planet tons of greenhouse gases.
Secondly, HCs also lower the Indirect GHG emissions compared to f-gases by maximizing energy efficiency through a combination of factors, including their favorable thermodynamic characteristics, a higher Coefficient of Performance (COP), and a low condensing temperature.
Hydrocarbons can replace many obsolete CFCs, HCFCs, and HFCs, and be used instead of HFOs and HFO blends, in domestic, commercial and industrial refrigeration. For example, hydrocarbons are a future-proof substitute for R134a, R404A, R407C, R507A or R449A in fridges, freezers, cascade supermarket systems, heat pumps, and chillers.
Moreover, hydrocarbons can replace harmful insulation foam-blowing agents. The hydrocarbon cyclopentane is now used as a viable alternative in hydrocarbon domestic refrigerators.
Hydrocarbon refrigerants are naturally occurring substances obtained when oil and gas are produced. They are easily available, globally, at extremely low costs.
No. Propane (R290) has a long history in refrigeration. It has been in use since before ozone-depleting CFCs were developed and was reintroduced for use in heat pumps after the CFC phase out. Its thermodynamic data, efficiency, and material compatibility are well known. In some countries, appliance manufacturers and food producers began using R290 as a replacement for R404A or R134a in appliances shortly after 2000, due to environmental concerns.
Hydrocarbons are more energy efficient than most conventional HFC or CFC systems. Used in residential air conditioning units, hydrocarbons have been reported to be 20-30% more efficient than synthetic refrigerants. A CO2-propane cascade supermarket system can save around 5% of energy, compared to an equivalent R404a system. Field tests with large AC chillers have shown that all energy-efficiency measures combined can result in a potential energy savings in excess of 50% for chillers that operate year round, when compared to minimum-initial-cost chillers that lack energy-saving features.
Hydrocarbons are suitable for use in the following applications:
- Domestic Refrigerators & Freezers: By far the largest application for hydrocarbon refrigerant to date. For example, R600a (isobutane) is used in more than one billion so-called “Greenfreeze” fridges and freezers worldwide.
- Commercial Refrigeration: R290 (propane) is mostly used as a replacement for the ozone-depleting substance R22 and HFCs in retail beverage coolers, medium-temperature cabinets, freezers. walk-in freezers and coolers, ice cube machines, vending machines, water coolers and restaurant fridges and freezers.
- Air Conditioning: Split AC for office and domestic use, portable AC, water-air AC, air-air AC, AC chillers, and dehumidifiers can use hydrocarbons.
- Mobile Air Conditioning (MAC): R290 is being used in transport refrigeration prototypes.
- Heat Pumps: R290 can be used in heat pumps.
Domestic fridges use up to 150g of R600a. Commercial cabinets currently use up to 150 g of R290 or R600a. However, the IEC has raised the international charge limit standard of hydrocarbons in commercial cabinets to 500g, and regional governments are now adopting that standard in whole or in part. Split-system air conditioners for office and domestic use do not use more than 300g of R290. Depending on the capacity, a heat pump could use from 500 g to 5 kg of R290.
A system using hydrocarbons works in exactly the same way as systems currently using synthetic refrigerants. The basic refrigeration cycle remains the same, and only the charge of the system (exact amount of refrigerant) varies.
Hydrocarbons are not “drop-in” or retrofit replacements for f-gases. There are significant differences between hydrocarbons and HFCs/HFOs that must be considered in handling, processing and application. Safety considerations must be applied in the design of equipment using hydrocarbon refrigerants, such as R600a and R290.
The two main advantages of hydrocarbon refrigerants are lower environmental impact and economic gains. First, hydrocarbons do not damage the ozone layer. Moreover, hydrocarbons can significantly reduce emission of greenhouse gases from refrigeration and air conditioning equipment. Because of their very low global warming potential, their impact on global warming from direct emissions is much lower. Hydrocarbons typically lead to much higher efficiency than traditional chemical refrigerants, thereby reducing energy consumption and greenhouse gas emissions related to them. In terms of economic benefits, besides energy-related savings, hydrocarbons can be easily implemented in conventional cooling systems, requiring minimal investment in components and design.
As hydrocarbons are classified as flammable in international safety standards, their use must follow certain guidelines, including charge limits, though these may vary somewhat from country to country. Guidelines for designing appliances for flammable refrigerants are available to meet safety standards. They specify that appliance producers manufacturing hydrocarbon systems must be equipped accordingly, and service technicians must be trained in safe handling procedures. Safety standards cover leakage simulation tests and specifications for the sealing of several electrical components which may come into contact with leaking hydrocarbons. There are international standards on electrical safety in place, for the following applications: household refrigerators and freezers, motor compressors, commercial refrigerators and freezers, heat pumps, air conditioners and dehumidifiers.
Household and some similar type appliances are limited to a maximum charge of 150 g. Commercial cabinets may still have a limit of 150g, but regions are beginning to approve higher charges up to 500g, per the latest IEC standard. You should consult the relevant local standards to determine how much hydrocarbon refrigerant can be used.
Domestic Refrigeration: By far, the biggest markets for hydrocarbons at the moment are domestic refrigerators and freezers. More than one billion of these appliances are in use globally.
Commercial Refrigeration: There were at least 5 million self-contained hydrocarbon display cases installed globally as of mid-2021.
Air Conditioning: R290 split air conditioners are being marketed in India and China, and are beginning to enter the European market.
Heat pumps: R290 is being used by a number of manufacturers in heat pumps.
More questions?
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Isobutane will be increasingly used in domestic fridges in the U.S., which began allowing this application over the last few years, joining the global adoption of R600a home fridges.
R290 and R600a will continue to grow as a refrigerant in self-contained commercial cases around the world, as more stores employ them for all of their refrigeration needs.
R290 will compete with R32 and other f-gases in the domestic AC market, and will become more widely adopted in heat pump applications.
