Taming heat with tiny pressure

Heat is almost everywhere. Unlike for electricity, which can be easily manipulated, the current ability to control heat is still highly limited owing to spontaneous thermal dissipation imposed by the second law of thermodynamics. Optical illumination and pressure have been used to switch endothermic/exothermic responses of materials via phase transitions; however, these strategies are less cost-effective and unscalable. Herein, we spectroscopically demonstrate the glassy crystal state of 2-amino-2-methyl-1,3-propanediol (AMP) to realise an affordable, easily manageable approach for thermal energyrecycling. The supercooled state of AMP is so sensitive to pressure that even several mega-pascals can induce crystallization to the ordered crystal, resulting in an substantial temperature increase of 48 K within 20 s. Furthermore, we demonstrate a proof-of-concept device capable of programming heat with an extremely high work-to-heat conversion efficiency of ∼383. Such delicate, efficient tuning of heat might remarkably facilitate rational utilisation of waste heat.