Development of a sustainable solid-state barocaloric cooler

Cooling is essential for food and drinks, medicine, electronics and thermal comfort. Thermal changes due to pressure-driven phase transitions in fluids have long been used in vapour-compression systems to achieve continuous refrigeration and air conditioning, but their energy efficiency is relatively low, and the working fluids that are employed harm the environment when released to the atmosphere.

We aim at developing the first energy-efficient barocaloric cooling prototype, based on novel barocaloric materials that are made of cheap abundant elements. Switching to such affordable efficient cooling technology would reduce the power consumption that is required worldwide for refrigeration and air conditioning, which is increasing particularly rapidly in low-income and lower-middle-income developing countries, and would obviate the need for harmful gases. Novel barocaloric refrigerators and air conditioners that are affordable and sustainable could therefore ease the looming energy crisis and protect the environment.

The overall objective of the proposed research project is to develop a barocaloric cooling demonstrator based on non-magnetic barocaloric materials that are made of cheap abundant elements, and that display outstanding refrigerant performance with superior energy efficiency, in order to assess the feasibility of a new solid state cooling technology based on barocaloric materials.

UK industry will be direct beneficiary of the proposed project. Beko will employ a mechanical engineer to work full time on the project at its Cambridge site, as a direct result of funding for the project. This funding assistance will free funds for additional collaboration between Beko and UK Universities. Beko will provide invaluable support in "grounding" the outputs of the project into real requirements of cooling systems.

The proposed research will address pressing challenges in the global field of energy efficient refrigeration and air conditioning, by combining materials science to identify materials with outstanding barocaloric performance, engineering to create new composite materials with enhanced barocaloric properties and suitable system designs, and manufacturing to fabricate the first-ever barocaloric cooling device, using insight gained from modelling of materials and device parameters. If successful, our ambitious strategy will culminate in a revolutionary solid-state barocaloric cooling device, the first of its kind, that is environmentally friendly and energy efficient.

Many households in developing countries do not have access to a refrigerator or cooling device, particularly in rural areas. For example, in India only 25% of refrigerator sales correspond to rural areas. A reduction in cost and an improvement in energy efficiency would allow those people living in rural regions greater access to refrigeration. An efficiency improvement would allow refrigeration via electricity generated by micro-generation (i.e. photovoltaics or wind) and battery storage. In addition, the barocaloric method of cooling requires the application of a low cycling pressure field, low enough that it may be provided mechanically by the user, which could possibly even enable hand- or bicycle-operated cooling devices. These advances would allow refrigeration devices to be run off-grid, improving access in rural areas, permitting setting up widespread cold chains for perishable foodstuffs, thus raising significantly food supply, by an estimated 0.65 billion tonnes of waste food per year, which could feed 1 billion more people, or vaccines, thus facilitating vaccine administration in remote areas, given that more than 90% of all vaccines must be chilled.

The deliverables of this project include publications, talks and patents. After protection of intellectual property rights, e.g. one year after the completion of the Early-Stage Award, the results from the research project will be reported in high-impact journals and presented at international conferences and workshops. All peer-reviewed scientific publications that arise from the research project will be open access, either (i) "green open access" by self-archiving the articles in an open access repository (e.g. University of Cambridge repository and arXiv), or (ii) "gold open access" by publishing in an open access journal using dedicated funds that are included in the proposal. The results will be also disseminated to the public through popular science literature, press releases and outreach activities.

The output of the project will be a barocaloric demonstrator that ultimately should make a very positive contribution to the reduction of the energy consumed in the cooling of buildings and vehicles, and thus the output of CO2 into the atmosphere. This will provide a very good platform for public engagement activity, and the University of Cambridge has very effective media communications and public engagement teams with collective experience of public engagement including BBC radio/TV.