The Future of Cooling with Natural Refrigerants--A Turning Point from CFCs 2001

The Future of Cooling with Natural Refrigerants--A Turning Point from CFCs 2001

The background was the international trend toward the phase-out of CFCs and the gradual reduction of HCFCs as a transitional measure under the Montreal Protocol, which aims to protect the ozone layer. HFCs, which became popular as alternatives to CFCs and HCFCs, do not destroy ozone but have a large greenhouse effect. Therefore, natural refrigerants such as CO2, ammonia, and hydrocarbons were reevaluated as an option to avoid the dichotomy.

In Japan, the world's first household CO2 hot-water heater, "Eco-Cute," was launched in 2001, followed by a succession of manufacturers, and since CO2 can efficiently pump air heat without combustion, it has helped to electrify hot-water supply and promote the low-carbon economy. The commercialization of this product in 2001 was a symbolic event in Japan's heat pump field, and was the result of collaborative technological development by the Tokyo Electric Power Company, Denso Corporation, and CRIEPI.

In Europe, hydrocarbons have been the mainstream refrigerant in household refrigerators since the 1990s, and as of 2001, almost 100% of German household refrigerators had converted to HC refrigerants, with "Green Freeze" leading the implementation of CFC-free refrigerants. This was an early example of mass adoption that demonstrated both climate and energy efficiency, with low GWP and high energy efficiency.

In industrial and commercial applications, ammonia refrigeration has been the standard for many years and is highly efficient, but requires safety design due to toxicity and material corrosiveness. CO2, on the other hand, was later popularized in supermarket trans-critical systems, with the first unit implemented in Italy in 2005, and expanded to other parts of Europe. around 2001 was an early stage of demonstration and design optimization, with the technical themes of pipe pressure, efficiency optimization, and adaptation to ambient temperature.

In Japan, the CFC Recovery and Destruction Law (promulgated in June 2001 and enforced in 2002) was enacted to institutionalize leakage control and proper disposal by requiring the recovery and destruction of CFCs from end-of-life equipment. This later evolved into the Comprehensive Law, which encouraged the market diffusion of natural refrigerants and low-GWP refrigerants.

In short, the period around 2001 was the starting point of the shift toward zero ozone depletion and low GWP refrigerants in the refrigeration and air conditioning fields, as the three factors of CFC control by international treaties, commercialization of natural refrigerants, and implementation of HC in Europe all came together. From this point, safety standards and equipment design optimization progressed, leading to today's best mix of CO2, HC, and R717 by application.