Update on CFC Substitutes in the USA With Respect to Vapor Compression Technology

The refrigeration industry has been in a state of flux primarily because of the phase-out of ozone-depleting CFC refrigerants, and secondarily because of recent advances in compressor technology. This paper contains a review of current substitutes for CFCs and HCFCs which are under consideration by the compression refrigeration industry, an assessment of their characteristics related to choice of one versus another substitute, and an identification of trends set by these choices. INTRODUCTION The HV AC&R industry has been a maturing industry for about fifty years. In its infancy, prior to the Second World War, there was virtually no air-conditioning in residential homes or automobiles, and for the most part food preservation relied on cooling with ice. Today, refrigeration has become essential to ensure the maintenance of food supplies throughout the world and air-conditioning is relied on to support the comfort and standard of living to which contemporary society has become accustomed. Industry has also developed an increased dependence on refrigeration technology. The electronics and chemical industries, for example, require this technology for the production of computer chips and for the manufacturing of synthetics. The driving forces in the HV AC&R industry are similar to those of many other technology-based industries. It is driven by political and economic factors, and by the introduction of new technologies. Two of the major global concerns are the fear of ozone depletion and global warming which has led to governmental and intergovernmental legislation regulations. Additionally, high costs of energy, new global suppliers, and global competition are among the many economic challenges faced by developing and developed countries alike. The availability of new compressors, materials, manufacturing processes, controls, refrigerants, and computational abilities entails expensive conversion costs for existing companies, but also offers opportunities for new ones. There are three major issues facing the HVAC&R industry. The first issue is what must be done to implement the phase-out of CFCs and HCFCs, driven primarily by their ozone-depleting potential. This phase-out is probably the single most important issue, and one which has effected greater changes in the HV AC&R industry in the last several decades than any other issue. Secondly, the need for more efficient equipment and systems in order to reduce energy consumption is a very important challenge facing the HV AC&R industry. This need first became evident during the "oil crisis" in the 1970s. More recently, the need for improved efficiency is also driven by the fear of "global warming". Finally, there is increased global competition due to the development of new suppliers of HV AC&R equipment. These companies see opportunities whenever new technologies become economically and technically feasible. Great improvements are currently being made in manufacturing, reliability, improved comfort, and the noise control of HV AC&R equipment. HISTORY AND FUTURE OF REFRIGERANTS Over the years, more than 50 chemical substances have been used as refrigerants in compression type refrigeration and air-conditioning systems, with varying degree of success. The very first machines, as developed by Perkins in 1834 and later by Harrison in 1856 used ether ("a fluid for cleaning printing type"), which was neither safe nor particularly suitable for the purpose. More appropriate compounds, like carbon dioxide (C02), ammonia (NH3), and sulfur dioxide (S02), were introduced in the 1870s and 1880s. These refrigerants were dominant for a long time, until the synthetic halocarbons, i.e. "Refrigerant-12" (CFzCh) at first and others later, took over much of the market from 1932 on. After the Second World