Empowering CO 2 Eco‐Refrigeration With Colossal Breathing‐Caloric‐Like Effects in MOF‐508b

Today, ≈20% of the electric consumption is devoted to refrigeration; while, ≈50% of the final energy is dedicated to heating applications. In this scenario, many cooling devices and heat‐pumps are transitioning toward the use of CO 2 as an eco‐friendly refrigerant, favoring carbon circular economy. Nevertheless, CO 2 still has some limitations, such as large operating pressures (70–150 bar) and a critical point at 31 °C, which compromises efficiency and increases technological complexity. Very recently, an innovative breathing‐caloric mechanism in the MIL‐53(Al) compound is reported, which implies gas adsorption under CO 2 pressurization boosted by structural transitions and which overcomes the limitations of stand‐alone CO 2 . Here, the breathing‐caloric‐like effects of MOF‐508b are reported, surpassing by 40% those of MIL‐53(Al). Moreover, the first thermometry device operating at room temperature and under the application of only 26 bar of CO 2 is presented. Under those conditions, this material presents values of Δ T ≈ 30 K, reaching heating temperatures of 56 °C and cooling temperatures of −10 °C, which are already useful for space heating, air‐conditioning, food refrigeration, and freezing applications.