The never-ending search

Abstract

Attending the 2014 Gustav Lorentzen Conference in Hangzhou, China, August 31 through September 2, reinforced my view that there is no consensus yet about which emerging refrigerants will be a long-term solution for heat pumping and refrigeration. Whatever fluids are under consideration force a compromise between mitigating local versus global perils (toxicity and flammability versus global warming). So, what does this mean for the research community? The obvious answer is the continued need for research that addresses the typical tasks: measurement of thermo-physical properties, of heat transfer coefficients, and pressure drop and finally the design and testing of new, well-matched heat pump components. These tasks are closely related to the actual performance of the fluid in a refrigeration or heat pumping system. In addition there more general tasks, such as flammability assessment, material compatibility, risk analyses, and time-intensive evaluation of short-term and long-term toxicity. It appears that these tasks become routine and are just a matter of cost. The less obvious approach could have the research community embarking on novel approaches. This could entail bringing non-vapor compression technologies to a performance and maturity level where it can displace conventional refrigerants, or developing heat pump designs for which the hardware functions well and is reliably independent of refrigerant choice, or pushing molecular thermodynamics to a level where accurate property predictions can be made based on the molecular structure alone. There may be new materials where leaks heal themselves, avoiding refrigerant leakage loss, or technologies that minimize charge to a degree where the direct global warming contribution becomes inconsequential. These are just a few examples, I am sure there are many more such ideas. It may be the outcome of these less conventional research goals that may eventually determine the technologies and/or fluids that will be in use for a longer term.