Nearly 50% of global final energy consumption is used for heating and cooling, divided roughly equally between industrial processes and residential or commercial buildings. These sectors cause significant air pollution and account for approximately 40% of energy-related CO₂ emissions. The refrigeration sector consumes 20% of global electricity – air conditioning alone accounts for 12%—and contributes 7.5% of global CO₂ emissions (30% from refrigerant leaks, 70% from energy use). Without intervention, refrigeration demand could at least double by 2050, increasing these pressures alongside enormous growth in heat pumps.

For decarbonisation, heating and cooling, as well as waste heat recovery – where around 50% of total global energy is wasted – offer far greater impact than fully decarbonising transport. The need for energy-efficient, environmentally friendly cooling, heat pumping, and air conditioning solutions has never been greater. Solid-state refrigeration and heat pumps are emerging as transformative alternatives, poised to replace some vapour-compression systems or address unmet needs. Their key advantages – tailored to specific subdomains – include recyclable, leak-proof refrigerants; vibration-free, silent operation; no moving parts; and superior theoretical efficiency. This presentation examines the applications and potential of solid-state systems across these domains, highlighting their role in improving energy efficiency and sustainability for diverse markets. It also addresses core challenges in a key solid-state technology, along with viable solutions and future directions.