A million times cooler: Elastocaloric materials can be used for solid-state cooling applications because they can pump heat out of a system using a reversible phase transformation. However, many such materials fail after a small number of cycles. Hou et al. found that laser melting of elastocaloric metals can create fatigue-resistant microstructures. A nickel-titanium–based alloy could be cycled a million times and still produce a cooling of about 4 kelvin. This processing method could improve elastocaloric performance and move us closer to using these materials more widely for solid-state cooling applications. Science , this issue p. 1116

Developing zero–global warming potential refrigerants has emerged as one area that helps address global climate change concerns. Various high-efficiency caloric cooling techniques meet this goal, but scaling them up to technologically meaningful performance remains challenging. We have developed an elastocaloric cooling system with a maximum cooling power of 260 watts and a maximum temperature span of 22.5 kelvin. These values are among the highest reported for any caloric cooling system. Its key feature is the compression of fatigue-resistant elastocaloric nitinol (NiTi) tubes configured in a versatile multimode heat exchange architecture, which allows the harnessing of both high delivered cooling power and large temperature spans. Our system shows that elastocaloric cooling, which only emerged 8 years ago, is a promising direction for commercializing caloric cooling.