For two days DTU Energy hosted the topical meeting Danish Days on Caloric Materials and Devices where some of the world’s leading researchers on novel caloric cooling technologies presented the latest research progress in the field.
87% of all American households have air conditioning. Worldwide, the annual sale is 120 million units, and by 2050 the total number of installed air conditioning units may reach 1.6 billion! On top of this, the use of refrigerators is growing strongly, particularly in the developing countries.
This will mean increased green house gas emissions. This is due to the fact that the most widely used refrigerants today are strong green house gasses. Studies show that emissions of hydrofluourcarbon (HFC) gasses used in refrigeration units will increase fivefold towards 2050, at which point they may account for as much as 10-20% of total greenhouse gas emissions. Clearly there is a strong need for energy efficient cooling technologies which do not use greenhouse gasses.
Here ‘caloric’ cooling technologies may play a role. These are technologies for refrigeration which instead of gasses use solids as the active materials. Some materials have the property that they heat up or cool down if they are subjected to a magnetic or electrical field, if they are stretched, or if they are put under pressure (these effects are called, respectively, the magnetocaloric, the electrocaloric, the elastocaloric, and the barocaloric effect). Refrigeration devices using such materials can be more efficient than conventional compressors used in refrigerators or air conditioning units. And water can be used to transfer the heat, making the refrigeration devices more environmentally friendly as well.
DTU Energy is among the world’s leading research institutions in the field of caloric cooling. This made it natural for the department to host the topical meeting Danish Days on Caloric Materials and Devices where the latest progress in the field was presented. With 32 presentations in two days participants from industry and research institutions had a busy schedule, and the discussions were lively. The participants could learn about everything from theoretical investigations of the atomic structure of caloric materials to the design and construction of wine coolers using the magnetocaloric effect.
The consensus was that a broad, interdisciplinary research effort is still needed in caloric cooling. Even though several prototypes have been demonstrated by companies and universities, the technology is still not economically competitive with the conventional technology. In this connection several participants stressed the importance of meetings like the Danish Days where researchers can learn about progress in related research areas and gain new inspiration, while industry can get an insight into the latest research in the field.