Environmental sustainability is the focus of MAYEKAWA's commercial activities. We have long pursued natural refrigerant technology and energy-efficiency solutions.

The application of natural refrigerants and thermal-engineering solutions that use less energy aim to support sustainable development, eliminate ozone layer depletion and stop global warming.
Natural refrigerants have a lower GWP (Global Warming Potential) than HFCs, as well as zero ODP (Ozone-Depletion Potential), making them environmentally friendly refrigerants. Mayekawa develops and manufactures a wide range of thermal engineering solutions, suitable for a vast range of temperatures in heating and cooling. We refer to this approach as the NATURAL FIVE: Five natural refrigerants; ammonia (NH3), carbon dioxide (CO2), water (H2O), hydrocarbons (HC) and air. These natural refrigerants are applied in heating, drying, hot water supply, air conditioning, cooling, chilling and freezing over a multitude of temperatures from -100degC to 200degC.
We have an intimate knowledge of heat pump technology using renewable energy including water, air and geothermal heat as a source of energy.

By pushing heat pumps to their technological limit we can capitalize on renewable and waste energy sources, at the same time preserving natural resources.

NH3 Ammonia

Ammonia is the most popular and traditional natural refrigerant

MAYEKAWA is developing minimum ammonia charging and safety operating systems.

For example, MAYEKAWA provides semi-hermetic motor drive compressors for the market.

We also promote NH3 / CO2 brine cooling systems because they can reduce the total ammonia-charging volume. 

This hybrid NH3/CO2 technology is deployed in our highly efficient systems in a range of temperature applications such as cooling systems for cold storage, ice rinks and compressors for freezer applications.

CO2 Carbon dioxide

CO2 gas as a refrigerant has an extremely low environmental impact. It has a Global Warming Potential (GWP) as low as 1/3920 of HFCs and CFC substitutes. CO2 is much safer: It is non-toxic, non-flammable and boasts superior cooling capacity. CO2 refrigerant gained much attention as a low-environmental impact refrigerant in the Montreal Protocol (MOP21) established in 2009.
MAYEKAWA offers safer cooling systems in which ammonia refrigeration packages cool CO2 as a secondary refrigerant. By doing this, NH3 refrigerant is eliminated from inside cold storage spaces and air conditioning systems.
Our CO2 refrigerant applications are not limited to chilling and refrigeration. We also offer heat pump systems for heating, hot water supply and drying with our MYCOM CO2 compressors.


MAYEKAWA has launched a freezing system using the air we breathe as the refrigerant. Air has no environmental impact; it is the ultimate natural refrigerant. Ideal for extremely low temperature applications (-50℃ - -100℃), this system can reduce absorbed energy and CO2 emissions by up to 50%.
It can be applied to conventional applications including super-low-temperature cold storage for frozen tuna fish and freeze-drying systems, as well as to other applications such as home appliance recycling plants (freeze-crushing), semiconductor production processes, medical & pharmaceutical processes and physical & chemical processes.

H2O Water

When water evaporates under vacuum conditions, it is cooled as its latent heat escapes through evaporation.
Principle adsorption chillers can continuously provide chilled water from 3℃ to 25℃ using waste or other water sources from 60℃ to 100℃. All this occurs without the use of mechanical compression as is the case with typical vapor-compression refrigeration systems.
Consequently, adsorption chillers provide industrial cooling and air conditioning with very low levels of absorbed power.

MAYEKAWA’s adsorption chillers can be used to chill water for air conditioning using solar energy as the heat source or to produce chilled water from industrial-process waste heat to reduce energy consumption.

HC Hydrocarbon

Hydrocarbon refrigerants have zero ODP, a GWP of less than three and are non-toxic.

HC operating pressure is lower than carbon dioxide (CO2) allowing for the use of standard compressors, and, while HCs have high combustibility, MAYEKAWA’s designs and safety equipment reduce associated risks to the level of other refrigerants.
MAYEKAWA has also developed HC heat pumps for air conditioning and hot water supply systems for centralized air heating and cooling systems where the use of natural refrigerants is still limited.
This system minimizes the refrigeration-leakage risk by using a compressor with a semi-hermetic motor. Integrated safety devices maintain refrigerant concentration at below LFL/LEL*. The system is designed to require only a minimum amount of refrigerant to maintain high safety levels even in the unlikely case that a refrigerant leakage occurs.
The hydrocarbon unit can be applied to heating and hot water supply up to 65℃, water chilling systems and ice storage systems.

*LEL: Lower Explosive Limit / LFL: Lower Flammable Limit