The potential of high-temperature heat pumps highlighted in the face of decarbonization challenges

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The decarbonization of the industrial sector presents challenges whose solutions sometimes bring new challenges of their own. This is the case with heat pumps, which are proposed as a pathway to decarbonization, but whose refrigerants pose environmental, safety, and operational problems. In response, an international group of researchers, with participation from the Spanish National Research Council (CSIC) through the Madrid Institute of Materials Science (ICMM-CSIC), reflects on the potential and opportunities of high-temperature heat pumps based on solid-state and gas cycles.

"Vapor compression is a very efficient method, but its refrigerants present environmental and safety problems. Furthermore, these techniques prevent heat pumps from operating at temperatures above 300 degrees Celsius," explains Miguel Muñoz Rojo, a CSIC researcher at ICMM and one of the authors of the study that analyzes the key findings in this field to demonstrate the potential of these technologies. "The development of technologies that can recover and pump heat at high temperatures is essential to utilize industrial waste heat and improve the efficiency of its processes," asserts the scientist.

This work, which has just been published in the journal Nature Energy, explains that, as current heat pumps cannot operate above 600 kelvin (equivalent to just under 326 degrees Celsius), "many industrial processes operating above this temperature use fossil fuels or resistive electric heating, generating a substantial amount of unused waste heat," adds the researcher.

"This makes it essential to develop technologies that efficiently recover and pump heat at such high temperatures," continues the scientist, who is in fact working on thermal modulators to improve battery performance thanks to an ERC Consolidator grant of two million euros.

In the study, the researchers highlight the opportunities and challenges of emerging and environmentally friendly high-temperature heat pump technologies based on solids or gases. "These technologies have the potential to supply heat at temperatures up to 1600 kelvin (nearly 1327 degrees Celsius), so we offer a perspective on possible solutions, applications, scalability, and a roadmap for future technological progress," notes the researcher.

"The greatest opportunity is that if we are able to pump that heat at high temperatures, we can improve the efficiency of industrial processes, truly contributing to decarbonization," continues the scientist, who is confident that "these advances in heat pumps will reduce fossil fuel consumption and facilitate the direct conversion of electricity into heat, while simultaneously utilizing currently untapped waste heat sources."