R&D topics

In this issue of the Newsletter dedicated to environmental issues, we present several initiatives related to promising refrigeration technologies or applications which have the potential to decrease the environmental impact of refrigeration plants thanks to increased energy efficiency of traditional vapour-compression systems and/or alternative technologies. As an introduction, some findings can be presented, based upon a recent paper by R. Radermacher. In the last 2 decades, R&D has focused on reducing first the ozone-depleting then the global-warming impact of refrigerants. "Natural refrigerants, especially carbon dioxide and hydrocarbons, are making inroads in some parts of the world. Meanwhile, other opportunities for the advancement of air-conditioning and refrigeration technology offer important and far-reaching opportunities that have potentially larger environmental benefits than refrigerant selections. One R&D area that can provide energy efficiency gains is improving the performance of cooling system components". As an example, "the development of oil-free compressors offers an important opportunity. The elimination of oil has the potential to significantly improve heat exchanger performance and will allow engineers to design a new generation of heat exchangers that go beyond flat-tube technology, with much smaller flow channels. Alternative cooling technologies such as thermoelectrics, thermoacoustics, acoustic compression, magnetic cooling, and gas cycles such as the Stirling cycle open up even more possibilities. When considering these alternative cooling technologies and what they do best, the initial success may come from skillfully integrating them with vapour compression rather than displacing vapour compression. One example may be the use of thermoelectrics for subcooling the refrigerant in a traditional vapor compression system". Radermacher concludes that instead of focusing on refrigerants which have little impact on total global warming, "a clear and convincing reduction in global warming potential results from aggressively pursuing energy efficiency improvements".