Information on the following topics is available below:

Greenfreeze Domestic Refrigeration
Commercial Refrigeration
Domestic and Commercial Air-conditioning
Ammonia Air-conditioning
Solar Air-conditioning
Desiccant, Evaporative and Absorption Cooling
Co-generation Cooling
District Cooling
Passive Cooling
Converting from fluorocarbons to natural refrigerants
Mobile Air-conditioning
Foam Alternatives


Greenfreeze Technology. Source: Greenpeace  

Greenfreeze Technology. Source: Greenpeace

There are over 750 million hydrocarbon, or GreenFreeze refrigerators in the world today. The GreenFreeze technology was developed by Greenpeace in 1992/93. The organization made the technology freely available to the world. The term GreenFreeze refers to refrigerators and freezers that contain no fluorocarbons. Typically, they use cyclopentane for the foam and isobutane (R-600a) as the refrigerant. The refrigerant charge of 30 to 100 grams varies according to the size and special features of the refrigerator. GreenFreeze refrigerators are available in all sizes, with typical standard and luxury features, including automatic defrost systems.

More than 100 million domestic refrigerators and freezers are produced in the world each year[1] and as of 2014 GreenFreeze technology represents around 40% of the total. It is projected that at least 75 to 80% of global new refrigerator production will use hydrocarbon refrigerants by 2020.[2] All of the major European, Japanese, and Chinese manufacturers now produce GreenFreeze refrigerators, with the technology now dominating these markets.[3]

GreenFreeze technology is also produced in South America with countries such as Argentina and Brazil in the forefront. In 2010, Brazilian power companies initiated a refrigerator exchange program, replacing older fluorocarbon models with new hydrocarbon based refrigerators.[4]GreenFreeze entered the Mexican market in 2009. The first lines of hydrocarbon refrigerators entered US markets in 2012.

Domestic GreenFreeze refrigerators are on average 25% more energy efficient than systems using fluorocarbons.[5]


Source: EIA

Commercial Refrigeration Units. Source: EIA
In 2010, commercial refrigeration accounted for approximately 1/3 of global HFC consumption.[6]This refrigeration subsector has the largest CFC, HCFC, and HFC CO2-equivalent refrigerant emissions.[7]There are three main types of commercial and industrial refrigeration equipment: (a) stand alone plug-in equipment, (b) condensing units, (c) centralized systems. Equipment using natural refrigerants is available for each of these applications.

There are a rapidly increasing number of companies around the world opting for natural refrigerants to meet their cooling needs. For example, in the supermarket sector, which is a prominent user of refrigeration, there is an exponential growth in the use of equipment and refrigeration systems working with natural refrigerants.  

In 2006, the number of supermarkets worldwide was estimated at 280,000, the number of minimarkets was estimated at 4 million, other facilities which had cooling condensing units was estimated to be at 34 million units. Furthermore, commercial retail stores, which had stand-alone refrigeration units (freezers, chillers and refrigerators), were estimated at 9.8 million.  Vending machines and other stand-alone equipment was also evaluated to be at 20.5 and 32 million units respectively.  All of this data gave an estimated refrigerant bank of approximately 340,000 MT, in 2006, for commercial cooling equipment; distributed at 46% in centralized systems, 47% for condensing units and 7% for stand-alone equipment.  All cooling functions of this sector can be met with natural refrigerants.

There is a tremendous growth in the installation of transcritical CO2 systems in supermarkets in many countries around the world. Europe leads the way. Between 2011 and 2013, the number of transcritical CO2 systems in Europe grew by 117%. Around 2,885 of these installations were in operation as of October 2013.[8]

Certain fluorochemical producers have proposed mixing hydrofluoroolefins (HFOs) with other HFCs to produce HFO-HFC blends for use in commercial refrigeration, such as DuPont’s Opteon and Honeywell’s Solstice line of HFO-HFC blends. HFO-HFC blends are not appropriate in new commercial refrigeration equipment:

  •  HFO Manufacture. The HFO manufacturing process is energy-intensive and expensive, requiring fluorinated feedstocks and produces fluorinated byproducts that contribute to ozone depletion and/or climate change.
  •  HFO-1234yf Usage. HFO1234yf is used in newly proposed blends being marketed as replacements for R404A and R507A. [9] HFO-1234yf breaks down into a strong and persistent acid, known as trifluoroacetic acid (TFA), which accumulates in aquatic and certain forest ecosystems with potential toxic implications for plants and animals whose long-term implications are unknown.
  • HFO Mixture. HFO-HFC blends contain mid- and high-GWP HFCs, such as HFC-32 (GWP 675), HFC-134a (GWP 1430), and HFC-125 (GWP 3500). Not only do the HFO-HFC blends themselves have unacceptably high GWP [10], but mixing HFOs with these HFCs only serves to prolong reliance on these problematic chemicals and could result in little to no net decrease in aggregate HFC emissions under current growth scenarios. 

From a technical and business perspective, HFO-HFC blends should not be used in new commercial refrigeration systems due to the availability of safe and energy-efficient technologies relying on natural refrigerants.


Godrej Eon Hydrocarbon Domestic AC Unit

Godrej Eon Hydrocarbon Domestic AC Unit. Source: EIA

There is an immediate need for environmentally sustainable domestic and commercial air-conditioning technology. Demand in this cooling sector is exponentially growing in both industrialized and developing countries as we experience ever-increasing temperatures around the world because of global warming.

As of 2011, the global inventory of stationary air-conditioners stood at approximately 790 million units. This included window and portable air-conditioners, single split type air-conditioners, multi-split type air-conditioners, ducted systems, small chillers, large chillers and centrifugal chillers. With rapidly increasing demand from Asia, by 2017 global annual sales are expected to be over 114 million units.[11]

There are natural refrigerant alternatives to HFCs for each of these A/C subtypes, some of which are currently undergoing tremendous developments. These include, in varying applications and configurations, hydrocarbons (propane R290 and propylene R1270), carbon dioxide, ammonia, water vapor (H20 or R-718). For example, hydrocarbon split air-conditioning in domestic use is set to make major inroads, in the immediate future, in both China and India, where top manufacturers have launched hydrocarbon production lines. China’s HCFC Phase-out Management Plan, under the Montreal Protocol, plans for 18 HCFC-22 air-conditioner production lines, with an annual output of 4.5 million units, to be converted to R290 by the end of 2015.[12] For split air-conditioners with cooling capacity of up to about 7 kW, hydrocarbons (R-290 or R-1270) can be widely used in wall and ceiling A/C units. A comparison of hydrocarbon charge sizes with the standard flammability limits indicates that hydrocarbons in split air-conditioners can be used in about 65% of the cases where HCFC/HFCs are currently used.[13]

Furthermore, there are numerous supermarkets, office buildings, public institutions, and other commercial enterprises in various countries that have installed HCFC/HFC-free cooling technologies using natural refrigerants. Natural refrigerant-based air-conditioning include carbon dioxide-based coolers, hydrocarbon primary systems, hydrocarbon- or ammonia-based secondary cooling systems, desiccant cooling, evaporative cooling, and absorption cooling. Consumers of cooling technologies must ensure that they chose the best available solution for their specific needs.


Ammonia has been used in refrigeration and air-conditioning since the 1850s. It has superior thermodynamic properties and is highly energy efficient. The most prominent example of the use of ammonia in air-conditioning is in the international space shuttle. Meanwhile, air-conditioning systems around the world, including universities, hospitals, hotels, office buildings, convention centers, and airports, also utilize ammonia.

Ammonia is also widely used in a variety of industrial cooling applications. Specifically in the foods industry, ammonia is used in various processes for cooling purposes. Europe is in the forefront of using ammonia in industrial processes. Furthermore, facilities are able to use ammonia for industrial processes as well as space cooling.


Solar Air-Conditioning System at U.S. National Guard Building in Arizona

Solar Air-Conditioning System at U.S. National Guard Building in Arizona. Source: US Army Environmental Command

The use of thermal energy in industrial processes covers a broad spectrum: from cooling for refrigeration and air-conditioning to reaching up to several hundred degrees in various production processes. Cooling is the second most critical production factor in industrial processes; such as for storing perishable goods, cooling in production processes and cooling the manufacturing equipment itself. In addition, cooling is becoming increasingly important for air-conditioning office buildings, shopping malls, hospitals and many other facilities. Solar cooling solutions convert solar thermal energy directly into cooling power by means of thermally driven chillers.  Solar energy solutions enable long term energy cost reductions. Combining solar energy with natural refrigerants offers the optimal environmental and business solution for cooling applications.

Solar cooling systems use sorption technology, which is a type of refrigeration cycle. (They could be either absorption [liquid-liquid] or adsorption [solid-liquid].) Sorption systems typically use either ammonia or water as the refrigerant. The refrigeration cycle is similar to a conventional vapor compression cycle, but instead of a compressor, it uses a combination of an “absorber” or “adsorber” and “generator” – these essentially work to bring the refrigerant from a low pressure gas to a high pressure gas, but using heat rather than electrically-driven mechanical compression. Since these systems require heat to drive them, solar energy can be utilized to provide that heat.


Desiccant cooling systems are basically open cycle systems, using water as refrigerant in direct contact with air. The thermally driven cooling cycle is a combination of evaporative cooling with air dehumidification by a desiccant (i.e., a hygroscopic material). For this purpose, liquid or solid materials can be employed. These systems use materials that attract moisture, thereby picking up humidity from incoming air and discharging it to the outdoors. The term “open” is used to indicate that the refrigerant is discarded from the system after providing the cooling effect, and the new refrigerant is supplied in its place in an open-ended loop.[14]

Desiccant cooling is widely used in the United States by supermarkets, chain department stores such as Wal-Mart, restaurants, hospitals, community centers, and office buildings. These systems use materials that attract moisture, thereby picking up humidity from incoming air and discharging it to the outdoors.

In 2007, Wal-Mart partnered with Munters Corporation to develop and implement a desiccant dehumidification system for its first “High-Efficiency Store” in Kansas City, Missouri. The system utilizes reclaimed heat from the refrigeration system to reactivate the desiccant system, thus allowing the normal air-conditioning equipment to run at a higher operating point. The system is expected to increase overall store energy efficiency by roughly 20%, and it is now being rolled out across the industry.[15]

Evaporative Cooling
Evaporative water coolers use heat in ambient air to evaporate water, which in turn cools the surrounding air. An evaporative cooler produces effective cooling by combining a natural process—water evaporation—with a simple, reliable air-moving system. Fresh outside air is pulled through moist pads, where it is cooled by evaporation and circulated through a house or building by a large blower. As this happens, the temperature of the outside air can be lowered as much as 30°F.[16] Sweating is a form of evaporative cooling of the body.

Evaporative cooling is especially efficient in dry climates, where the installation and operating costs can be significantly lower than a traditional refrigerant system. Direct, or single-stage, evaporative coolers are used on tens of thousands of homes in the western United States, as well as thousands of commercial establishments-shops, restaurants, dry cleaners, offices, warehouses, factories. They are also sold as small, portable units to cool individual rooms.

In the United States, more than 70 companies manufacture evaporative air-conditioners for residential, automotive, commercial, and industrial markets.

Indirect-direct, or two-stage, evaporative air-conditioning systems are also used in numerous applications such as schools, office buildings, commercial buildings, and homes. These systems precool air in the first stage by running it through a heat exchanger; thus, the final cooled air has less humidity than in a direct or single-stage system.

Absorption Cooling
Absorption systems use a heat source, such as natural gas, propane, or waste heat from a variety of processes, instead of electricity. They are used in a wide variety of commercial settings, including banks, airports, office buildings, apartment buildings, hospitals, convention centers, and large residences. They typically use water as the refrigerant and lithium bromide as the absorber. Most of the installations noted use natural gas–fired chillers, though an increasing number use solar energy as the heat source. European countries, such as Spain, Germany, and Greece, have been leaders in implementing large-scale solar absorption coolers.

It is important to check the primary energy ratio (PER) to determine whether or not an adsorption or absorption system is energy efficient. In regions where there is a low emission factor (kg CO2/kW h of electricity), then the use of direct-fired sorption systems could be much less efficient then compression systems.


Air-conditioning technologies based on the use of waste heat from on-site electricity generation have the potential to greatly reduce energy consumption. This eliminates HFC use in many large-scale applications immediately.


Cornell University District Cooling System

Cornell University District Cooling System. Source: Cornell University

A district cooling system (DCS) distributes thermal energy in the form of chilled water or other media from a central source to multiple buildings through a network of underground pipes for use in space and process cooling. The cooling or heat rejection is usually provided from a central cooling plant, thus eliminating the need for separate systems in individual buildings.”[17]

DCSs today rely on a variety of cooling agents, including HFCs, ammonia, water, or the use of absorption chillers. However, the use of HFCs for DCSs is unnecessary because natural refrigerants are available and can be safely applied in large chillers. And DCSs using absorption chillers can use mixture of lithium bromide and water, “which is a more environmentally benign alternative than the cooling agents used in building-specific compressor plants, is used as a cooling agent in absorption chillers.”[18]

Regardless of the refrigerant used, DCSs are a highly efficient way of delivering cooling services with potential to reduce consumption of electricity for cooling purposes by as much as 90%.[19] A centralized cooling system provides greater quality control in maintenance and servicing, reducing the rate of refrigerant leakage.

DCSs displace peak electric power demand with district cooling and storage using ice or chilled water. This benefits the local power grid by reducing peak power demand and alleviating power congestion because of power transmission limitations in cities. So district cooling not only helps cool cities, it also helps alleviate the challenges posed by high electric consumption. The economic benefits can be experienced by both the owner and the tenant, where the capital costs of control panels, internal power distribution, annual maintenance, and power consumption inside the building are reduced and the cost of chillers is eliminated.”[20]

Benefits of district cooling include:

  • Better quality of cooling
  • Capital cost elimination
  • Decrease in sound pollution
  • Maximum cost-effectiveness
  • Space saving
  • Environmentally friendly

Common applications involve district-cooling utilities that sell chilled water to numerous customers, as well as single owner-operator-customer systems such as universities, hospitals, airports, and industrial facilities. DCSs often facilitate the use of other beneficial technologies, such as non-electric and hybrid (electric and non-electric) chiller plants, cogeneration, and trigeneration, and thermal energy storage.”[21]

DCSs exist in many parts of the world. There are about 100 DCSs in Europe.[22] In the United States, there are approximately 2,000 DCSs, which cool 33,000 commercial buildings, plus numerous schools, institutions, and residences.  They have also been installed in the Middle East and in Singapore.


Prior to modern refrigeration technology, people kept cool using natural methods: breezes flowing through windows, water evaporating from springs and fountains, as well as large amounts of stone and earth-absorbing daytime heat. These concepts were developed over millennia as integral parts of building design. Today they are called passive cooling. Passive cooling is based on the interaction between the building and its surrounding.[23] In some places, passive cooling can be used instead of mechanical cooling. In other places, the two can complement one another.

The architectural redesign of new buildings to make use of natural ventilation, coupled with efficient insulation, can eliminate or reduce the need for mechanical air-conditioning and thus save energy.


                             Swabhumi Hotel complex

                               Swabhumi Hotel complex

                                                   Models of the Swabhumi Hotel complex. Source: Greenpeace

The Swabhumi Hotel complex in Kolkata, India, designed by architectural firm Morphogenesis, uses innovative building design that simulates the way trees trap winds to deliver cooling services. The firm also designed the Pearl Academy of Fashion (shown below) in Jaipur, where classrooms are cooled to around 25°C without air-conditioners, while ambient temperatures are nearly double outside.[24]


Terry Thomas Office Building, Seattle. Source: Greenpeace

The Terry Thomas office building in Seattle, Washington, designed by Weber & Thomson, requires no air-conditioning. The building has green-tinted glass shades (or sunglasses) that shield windows from heat, while still allowing light into the building. Heat-reflective coating on the windows also reduce temperatures. The 40,000 square foot structure has a central courtyard, which allows cross breezes to enter all parts of the building, and allows more natural light into the building.[25]

It is widely accepted that propane and other hydrocarbons are the optimal alternative, nearly drop-in replacements for HCFC-22. Companies like Ecozone of the Netherlands, Energy Resources Group of Australia, Nat Energy Resources Private Limited of Singapore, Maple Edge Sendirian Berhad in Malaysia , APL ASIA Co in Thailand, as well as Econergy Engineering Services Ltd  and Rexham Engineering Services Ltd. in Jamaica have completed numerous conversions of R-22 installations to hydrocarbons with significant energy savings. These conversions of used equipment demonstrate that hydrocarbons can be safely applied and should be an incentive to equipment manufacturers to produce new air-conditioning units with propane and other hydrocarbons.

Safety considerations: The advantage of converting to a hydrocarbon refrigerant is that it is environmentally friendly, and little or no changes need to be made to the retrofitted air-conditioning units. However, it must be ensured that the system is left in a safe condition, and that it adheres to the requirements of relevant safety standards applicable for HC refrigerants. Generally, this demands alterations to electrical components, application of marking and warning signs, and certain other changes. See Guidelines for the Safe Use of Hydrocarbon Refrigerants.


In 2014 it is estimated that there are at least 400 million cars with mobile air conditioning (MAC) units.[26] The total stock of refrigerant charge from the global fleet of passenger-cars was 70,100 tons in 2006, with an average leakage rate of approximately 17%.[27] Since then there has been exponential growth in total volume of refrigerant used in MACs. Currently, almost all new  MAC units use HFC-134a refrigerant, accounting for 30 to 50% of total  HFC emissions.[28] In Europe, under the MAC Directive, HFC-134a ,and all other HFCs with a GWP of 150 or more, are prohibited in all new cars and vans introduced into the EU from 2011 and in all new models placed on the market from 2017.[29]

The US Environmental Protection Agency found that vehicles are the largest source of HFC emissions. They account for 56% of annual total HFC emissions in the United States. A 2014 study based on 2006 greenhouse gas usage, estimated that air-conditioning accounts for over 4.2% of a vehicle's total greenhouse gas emissions.[30]

The US Department of Energy's Energy Information Agency Web site states that "Automobile air conditioners are subject to leakage, with sufficient refrigerant leaking out (15 to 30 % of the charge) over a 5-year period to require servicing.”[31]

A 1997 study by Atlantic Consulting reveals that the HFC-134a leakage from the air-conditioning of cars sold in 1995 in Western Europe alone will generate the CO2-equivalent emissions of five new power plants, while the HFC-134a leakage from automobiles sold in Japan in 1995 will contribute the CO2-equivalent of ten power plants, or approximately 16 million tons of CO2. A study by the School of Chemical Engineering and Industrial Chemistry, University of New South Wales, indicates that hydrocarbon automobile air-conditioners are almost 35% more efficient than HFC air-conditioners. They also found that, if countries in Asia used hydrocarbons instead of HFCs in automobile air-conditioners, there would be 3.7 billion tons less cumulative CO2-emissions by the year 2020.[32]

Hydrocarbons in MACs
Hydrocarbons offer reliable alternatives to both CFCs and HFCs in mobile air-conditioning (MACs). The 2010 UNEP RTOC Report notes: “HCs or HC-blends, when correctly chosen, present suitable thermodynamic properties for the vapor compression cycle and permit high energy efficiency to be achieved with well designed systems.”[33]

In 2002, the Mobile Air Conditioning Society (MACS) performed a survey that found 2% of vehicles presented for repair in the United States were charged with hydrocarbon refrigerants, which equates to over 4.2 million vehicles.[34] Similarly, a study by the University of New South Wales estimated that 4.7 million US vehicles were charged with hydrocarbons as of 2004. The same study also documented extensive use of hydrocarbons in Australian vehicles.[35] A 2013 Australian study reported that approximately 8% of the country’s  entire registered vehicle fleet use hydrocarbons.[36]

Though at the present time there are no hydrocarbon-based mobile air-conditioners sold on the world market for passenger-cars, Greenpeace estimates that, globally, up to 50 million cars may have been converted, outside of regulatory framework, from CFCs and HFCs to hydrocarbons.[37] Such routine drop-in conversions are taking place in Australia, United States, Canada, China, Panama, Philippines, Indonesia, Korea and some Caribbean countries.

Standards and safety considerations using hydrocarbons             
Since hydrocarbons are flammable, conversion from HFCs to hydrocarbons must follow standard safety procedures.

Direct Systems MAC Cooling: Hydrocarbons could be safely used in direct systems in new MAC equipment specifically designed for their usage. This would encompass keeping hydrocarbons away from spark and heat sources, automatic switch offs in case of leaks, leak detection devices, and ventilation systems.

Secondary Loop Hydrocarbon Systems: The application of a secondary loop system would further overcome any outstanding safety concerns. "Designed to accommodate a hydrocarbon, the secondary loop system would completely eliminate HFC-134a use (and emissions).” It would be expected to use about 10% more energy for operation than the current system but would still represent a net savings of at least 80% of equivalent greenhouse gas emissions associated with current HFC-134a systems that are operated without proper recovery and recycle during service and vehicle disposal.[38]

One noteworthy aspect of using propane, the best hydrocarbon choice for secondary loop systems, is its availability. Propane is used universally for heating and cooking. As a result, its safe handling is widely understood and practiced by the general population in most countries, whether literate or not. This could be an advantage in the developing countries. For systems using propane, the charge for a midsize vehicle would be relatively small, on the order of 200g, based on the molecular weight of the refrigerant and the lower refrigerant charge required by the secondary loop system."[39]

Carbon dioxide in MACs
The energy efficiency benefits of CO2 systems have been known for several years. Extensive measurements carried out in 1999 at the University of Illinois showed that CO2 MACs have at least 30% lower TEWI  than HFC systems.  Other studies reporting on trials comparing CO2 prototypes against state-of-the-art R134a systems in real situations indicate that the COP of the CO2 system was typically 25% greater than that of the R134a system.  Based on the Life Cycle Climate Performance (LCCP), a study by SINTEF research institute compared MAC systems’ total contribution to global warming with a cradle to grave approach, highlighting several benefits of R744 MAC-systems concerning environmental performance, costs, and future potential. Namely, the R744 MAC produced up to 40% lesser emissions in hot climates (India and China) than R134a.

In addition to their environmental benefits, CO2 systems provide a servicing cost benefit, as there is no need to recover and recycle the refrigerant at the end of life.[40]

HFC-1234yf (HFOs) in MACs

Certain fluorochemical producers and car manufacturers have proposed using so-called hydrofluoroolefins (HFOs) in passenger vehicles and other mobile air conditioning (MAC) systems. As synthetic chemicals with adverse impacts on human health and environment during their manufacture and use, HFOs are not the solution for several reasons:

  • HFO Manufacture. The HFO manufacturing process is energy-intensive and expensive, requiring fluorinated feedstocks and produces fluorinated byproducts (including HFC-23 with a GWP of 14,800) that contribute to ozone depletion and/or climate change.
  • HFO Usage. The use of HFOs such as HFC-1234yf is associated with the formation of explosive gas mixtures and toxic hydrogen fluoride (HF) in the event of fire or explosion.[41]


    HFOs also break down into a persistent, non-biodegradable acid known as trifluoroacetic acid (TFA), which accumulates in aquatic and certain forest ecosystems with potential toxic effects on plants and animals whose long-term implications are unknown. [42]


    In addition, HFOs are significantly more expensive than HFC-134a, as much as 10 times more expensive. This is likely to spur illegal use of HFC-134a or even HCFC-22 in the aftercare market in the MAC sector as they can operate in the HFO systems, thus negating future climate benefits and resulting in illegal trade.

In contrast, natural refrigerants such as CO2 and hydrocarbons achieve high efficiency and are better suited for cooling and heating in passenger vehicles without adverse impacts on human health and the environment.

Natural blowing agents such as pentanes or CO2 can be used in all types of foam production. Several large manufacturers have been successfully using the technology for many years to produce high-quality products.[43] As demand for foam rises, in large part to improve insulation for housing and buildings, it is increasingly important that foam be manufactured wihtout high-GWP blowing agents. For example, today hydrocarbons are widely used in susbtantial part of the market in the foaming sectors of both industrialized and industrializing countries. In Europe and Japan, hydrocarbons blends have been the dominant blowing agent of choice since the CFC phase-out began in the 1990s. Hydrocarbons have a significantly greater blowing efficiency than conventional synthetic refrigerants. For example, 170,000 tonnes of hydrocarbons used in 2014 will predictably generate 30-40% more blown foam than would be achieved by the same volume of CFCs.[44] Technological advances in hydrocarbons have also resulted in significant thermal efficiency improvements over the years.[45]

Rigid Extruded Polystyrene (XPS)
Extruded polystyrene is used as a rigid board stock, where its moisture resistance and strength make it suitable for below-the-ground construction insulation, for example, in foundations and basement walls. Developed countries commonly use HFCs, and developing countries are still primarily using HCFCs as blowing agents, but many alternatives are emerging and being increasingly used worldwide. Water-based blowing agents and hydrocarbons are now commonly used. “It is not necessary to use HFCs as blowing agents in rigid XPS foam for the construction sector. The entire product range can be produced with CO2 as blowing agent or using a combination of CO2 with 2 to 3% ethanol. Overall, the target should be a complete phase-out of HFCs in the production of rigid XPS foam.”[46]

Flexible Foams
Compared with rigid foams, flexible foams can be deformed when exposed to pressure, a characteristic required, for example, in mattresses and other furniture. In the 1990s, new techniques were developed to produce flexible foam without CFCs, including variable pressure foaming (VPF), which creates CO2-based foam from the reaction of isocyanate and water. No blowing agents are required in this process.

Flexible foams are often used for non-cooling products like furniture, automotive applications, safety devices, and noise insulation. Many manufacturers have already switched to this process. For example, in 1998, the Multilateral Fund helped fund the conversion of four companies in Argentina from CFC-12 to carbon dioxide–based foam for mattresses, accounting for 90% of the Argentinean market.

Rigid Polyurethane (PUR)
Rigid PUR insulating materials are closed-cell, rigid plastic foams that are available in many forms. Most often, this type of foam is used in construction, as in flexible-faced laminates, sandwich panels, slabstock or boardstock, spray foams, and pipe insulation. It is also used in appliance insulation.

HFC replacements for HCFC-141b in rigid polyurethane (PUR) foam include HFC-245fa, HFC-365mfc, or HFC-134a.  These are potent global warming substances.  For the most part they are unnecessary as there are natural blowing agents to replace HCFC-141b in most foaming applications. In 2013, hydrocarbons represented over 55% of global blowing agent usage, and are expected to grow by 5.8% by 2019.[47]

Hydrocarbons have become the most widely applied technology in the world for PU foams. Whereas it is sometimes reported that the thermal performance of hydrocarbons is inferior in comparison to HFCs in foams, optimized hydrocarbon foam technology today yields equal  performance to that of HFC-based foams.[48]

Appliance insulation foam is used to insulate refrigeration appliances, hot water storage tanks, and similar products. With the exception of the North American market, cyclopentane is the standard choice for the rigid PUR in domestic appliances and small commercial equipment.

Germany has been a leader in converting to cyclopentane in appliances and has fully converted to this technology in domestic refrigerators. General Electric in the United States might soon be the first to enter the North American market with cyclopentane foam in new refrigerator-freezers set for production next year.

In the commercial sector, Electrifrio in Brazil switched to cyclopentane based foam for refrigerated displays for chilled and frozen foods and cold stores for large supermarkets back in 1996.

In 2011, Dow introduced the Pascal technology, which is a patented, high-efficiency hydrocarbon-based polyurethane foam system for commercial and residential appliances.  The Pascal system allows users to meet the US EPAs new, stricter energy efficiency regulations; the technology allows for 10% greater energy efficiency over current PU insulating systems.[49]

Methyl formate is also increasingly used in this sub-sector.

Flexible-Faced Laminates
Flexible-faced laminates are used as insulating panels in the housing sector to insulate floors, saddle roofs, or under floor heating systems. Until 2004, HCFC-141b was mainly used. Today, rigid PUR insulating panels for building construction are often foamed with pentane. In Germany, 90% of flexible laminates use pentane.

Boardstock is mainly used as roof and wall insulation in commercial buildings, and companies are increasingly using pentane as a blowing agent in these panels. Currently, hydrocarbon foams are mainly used in developed countries, whereas developing countries are still using HCFCs.

Sandwich Panels

Sandwich panels usually have foam sandwiched between materials such as steel and aluminum, and are often used to insulate roofs and walls in industrial refrigerated warehouses and cold stores. Cyclopentane is now commonly used as a blowing agent in sandwich panels, and the process has been optimized to the point where the thermal insulation is better than that of most HFCs. By 2002, four of the six large panel foam manufactures in Argentina had switched from CFC-11 to pentane as their foam-blowing agent. Methyl formate is also increasingly used in this sub-sector.

Spray Foams

Spray foams now increasingly use CO2  as a co-blowing agent with HFCs. In Japan super-critical CO2  is used, and the performance of this, while not quite equivalent to HFCs and HCFCs it replaces, is still improving and already suitable for many applications.[50]

Pipe insulation

Pipe insulation can now be manufactured with cyclopentane and has the same performance as HFC-365mfc, the common refrigerant used. More than half of the world production of pre-insulated district heating pipes takes place in Denmark, by four companies: ABB District Heating (I C Moller), Logstor Ror, Taco Energy, and Star pipe (Dansk Rorindustri). All four companies are now producing insulation using cyclopentane or other hydrocarbons. Two of the companies also produce CO2-based pipes.

Alternatives to foam

Often the best alternatives to polyurethane boardstock are not foams at all. Magnesium carbonate, as produced by Darchem in the United Kingdom, can be made into an insulation product for use in power stations and oil installations. Products such as mineral fiber and fiberboard have always been in competition with polyurethane. Mineral fiber is dominant in insulation products in the United Kingdom. Meanwhile, the Swiss company Isofloc produces boardstock panels made out of cellulose. The panels are made out of recycled materials.

Vacuum insulation panels, which offer superior insulation for appliances and provide significant energy savings are increasingly being applied. These vacuum panels are filled with, for example, silica, fiberglass, or ceramic spacers.  A global manufacturer and supplier of this type of technology is Microtherm Thermal Insulation Solutions, based in Europe and Asia. 

In addition to foams manufactured with natural blowing agents, a combination of rock wool and aerogel offers efficient HFC-free insulation. Rock wool insulation refers to a type of insulation that is made from actual rocks and minerals. It also goes by the names of stone wool insulation, mineral wool insulation, or slag wool insulation. A wide range of products can be made from rockwool, due to its excellent ability to block sound and heat. Rock wool insulation is commonly used in building construction, industrial plants, and in automotive applications.[51]

[1]Öko-Recherche et al, “Preparatory study for a review of Regulation (EC) No 842/2006 on certain fluorinated greenhouse gases” : 2010. p274. Available: annex_en.pdf

[2]UNEP,“Technology and Economic Assessment Panel 2010 Progress Report: “Assessment of HCFCs and Environmentally Sound Alternatives,”: 2010, p.37


[4]Ozchill, "Refrigerator exchange programme in Brazil" : 2010,

[5]Engas, “About hydrocarbon refrigerants” : 2014 ,

[6]U.S. EPA, “Fact Sheet: “Transitioning to low-GWP alternatives in commercial refrigeration”: 2010

[7]IPCC/TEAP, “Potent Greenhouse Gases: Ways of Reducing Consumption and Emission of HFCs, PFCs 7 SF6”: report prepared for the Nordic Council of Ministers: 2005 as reported in TemaNord 2007, p.32

[8], “New European map shows: CO2 transcritical supermarkets more than double in two years”: 2014

[9] R449A and R448A are being proposed as replacements for R404A and R507A. R449A is a blend of R32 (24.3%), R125 (24.7%), R1234yf (25.3%) and R134a (25.7%) with a GWP of 1397, sold by Dupont as Opteon XP40. R-448A is Honeywell’s proposed replacement, sold under the trade name Solstice N40. It uses the same components as DuPont’s R449A with the addition of a small amount of R1234ze(E). Its composition is R-32 (26%), R125 (26%), R1234yf (20%), R134a (21%) and 1234ze(E) (7%).

[10] DuPont, PowerPoint Presentation (undated), pp. 19-21 available at (Opteon XP10 has a GWP 630, Opteon XP40 has a GWP 1397, and Opteon XP44 has a GWP 2140; Honeywell, Solstice Range of Refrigerants, available at (Solstice N13 has a GWP ~600, Solstice N20 has a GWP ~1000, Solstice L20 has a GWP ~300, Solstice N40 has a GWP ~1380, Solstice L40 has a GWP ~300, and Solstice L41 has a GWP ~600).

[11]Transparency Market Research, “Air Conditioning Systems Market- Global Scenario, Trends, Industry Analysis, Size, Share and Forecast, 2012- 2018”: 2013, http:/

[12], “China’s major refrigerant suppliers expand R600a and R290 production”: 2012, http:/

[13]European Commission, “Op.Cit Preparatory study for a review of Regulation”: 2011, p.195

[14]Solair Project: 2010,

[15]Wal-mart Press Release, “Wal-Mart to Open First High-Efficiency Store; Supercenter Expected to Use 20 Percent Less Energy: January 18, 2007,

[16]Consumer Energy Centre: 2013,

[17]National Climate Change Commission, Singapore :2014,


[19], “District Cooling Benefits”: 2012,

[20] Coolsolutions Company,

[21] U.S. Energy Information Administration, “Consumer Commercial Buildings Energy Consumption Survey (CBECS)”: 2003,


[23]Vancouver Sun, “Reuters report”: March, 2008, Meta




[27]European Commission, “Preparatory study for a review of Regulation No 842/2006 on certain fluorinated greenhouse gases”: September 2011

[28]IGSD, “Update on the HFC phase-down in mobile air conditioning”: 2014,

[29]European Commission, “Enterprise and Entry-Mobile Air Condition Systems”: 2014,

[30]Congressional Research Services, “Cars, Trucks , and Climate: EPA Regulation of Greenhouse Gases from Mobile Sources”: 2014,

[31]U.S. Energy Information Administration, “Hydrocarbons and other Gases”: 2008,

[32]Pham, Tuan and Aisbett, E. “Natural Replacements for Ozone-Depleting Refrigerants in Eastern and Southern Asia: School of Chemical Engineering and Industrial Chemistry, University of New South Wales,” to be published by the International Journal of Refrigeration, in press 1998

[33]UNEP, “Report of the Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee”: 2010 Assessment Report; p.163.

[34]Mobile Air Conditioning Society Worldwide, “MACs releases Refrigerant Survey Results”: Lansdale PA, USA, October 2002, p.2

[35]Professor Ian Maclaine Cross of the University of New South Wales, “Usage and Risk of Hydrocarbon Refrigerants in Motor Cars for Australia and the United States”, International Journal of Refrigeration, Vol. 27, No 4, 2004, pp.339-345

[36]"Cold Hard Facts2” A study of the refrigeration and air conditioning industry in Australia: July 2013, Prepared for the Department of Sustainability, Environment, Water, Population and Communities.

[37] Greenpeace estimate is based on above-mentioned surveys, annual growth-rates and direct stakeholder consultations

[38] S.O. Anderson, U.S. Environmental Protection Agency, Washington DC, USA, W. Atkinson & J.A. Baker Technical Advisors to the Mobile Air Conditioning Climate Protection Partnership Existing and Alternate Vehicle Air Conditioning Systems.

[39] Ibid.

[40]Multisectorial Initiative on Potent Industrial Greenhouse Gases (MPIGGs) newsletter, 2004:

[41] ProKlima, “Natural Foam Blowing Agents: Sustainable Ozone and Climate Friendly Alternatives to HCFCs”:2009,

[42] Umweltbundesamt (German Federal Environment Agency), Natural Refrigerants for Mobile Air-Conditioning in Passenger Cars: A Contribution to Climate Protection (September 2010), pp. 4-5.

[43]G.E. Likens et al., Proceedings for the National Academy of Sciences, Transport and Fate of Trifluoroacetate in Upland Forest and Wetland Ecosystems (April 1997) Volume 94, pp 4499-4503; see also Hideo Kajihara et al., Estimation of Environmental Concentrations and Deposition Fluxes of R-1234yf and its Decomposition Products Emitted From Air Conditioning Equipment to Atmosphere (17-19 February 2010); Environmental Working Group, Teflon Toxicosis Is Deadly to Pet Birds: Are We At Risk? (15 May 2003); Boutonnet et al., Environmental Risk Assessment of Trifluoroacetic Acid: Human and Ecological Risk Assessment (1999), 5(1), 59–124.

[44]UNEP, “Technology and Economic Assessment Panel Volume 4: Decisions XXV/5 Task Force Report Additional Information to Alternatives on ODS (Draft Report)”: 2014, p20,


[46]German Federal Environmental Agency (Umwelt Bundes Amt), “Avoiding Fluorinated Greenhouse Gases: Prospects for Phasing Out”: August 2011, p. 147,

[47]MarketsandMarkets, “Blowing Agents Market by Type (HCFCs, HFCs, HCs & Others), by Foam Type (PU, PS, Phenolic, Polyolefin, & Others) & Geography - Trends and Forecasts to 2019”: 2014

[48]UNEP Technology and Economic Assessment Panel. Task Force Decision XX/8 Report: Assessment of Alternatives to HCFCs and HFCs and Update of the TEAP 2005 Supplement Report Data; 2009

[49]DOW Polyurethanes, "PASCAL™ Technology – the PU Energy Efficiency Solution" : 2014,

[50]U.S. EPA, “Transitioning to low-GWP alternatives in building/construction foams”: 2010,

[51]German Federal Environmental Agency [Umwelt Bundes Amt]. “Avoiding Fluorinated Greenhouse Gases: Prospects for Phasing Out”. August 2011, p. 154.