Fighting the climate crisis with caloric heat pumping: Innovations to enable widespread adoption

Abstract

Caloric heat pumping is a cross-cutting thermal energy technology that can cover a wide range of applications and temperatures, from millikelvins to hundreds of kelvins, with a working medium that has zero global warming potential. The technology promises cost savings and high efficiency, having 60% Carnot efficiency demonstrated to date. The Energy Earthshots™ Initiative, launched by the U.S. Department of Energy, aims to fight the climate crisis and overcome technological barriers to a decarbonized economy. The initiative focuses on the development of energy solutions that increase efficiency, reduce greenhouse gas emissions, and ensure affordability. Three out of eight Energy Earthshots™ look for alternative thermal energy technologies for extensive temperature ranges, from hydrogen liquefaction to metal-treating temperatures. Caloric heat pumping can fulfill all these requirements; however, at the current stage, caloric systems have limited presence in real-world applications. This perspective discusses key efforts to address barriers hindering the widespread adoption of caloric technology. We focus on essential breakthroughs in and effective approaches to material discovery and draw a path to high-power-density, grid-interactive caloric systems to support achieving the ambitious net-zero carbon economy goal.

Highlights

The climate crisis we face calls for energy-efficient, eco-friendly, and cost-effective solutions, and one of them is caloric heat pumping with applicational potential ranging from cryogenic temperatures to hundreds of kelvins. In this perspective, we discuss the high potential of this technology to provide climate solutions along with barriers to its adoption and outline the necessary innovations to transform it into a sustainable and competitive choice for the future.

Discussion

Conventional liquefaction process consumes ~ 35% of the liquid-hydrogen energy content. This drives up the price and hinders its use as a clean, lightweight fuel.

Over 20% of households in the U.S. struggled to pay their energy bills on time in 2022. Energy insecurity affects residents of less energy-efficient homes.

The average emission rate of industrial heat in U.S. factories is 65 kg CO₂e/MMBtu. Burning fossil fuels and the release of co-pollutants have a negative impact on the health of nearby communities.

Gas refrigerants, used in a wide range of thermal applications, often have high global warming potential or other harmful effects. ~ 10–20% of installed refrigerants leak annually.

Caloric heat pumping is a clean, efficient thermal energy technology that can help meet demands to decarbonize the global economy.

Graphical Abstract