Architecting\nUltra-Robust Zr(IV) Metal–Organic\nFramework for Energy-Efficient Desiccant Air Conditioning

Air-conditioning\nsystems, composed mainly of humidity control and\nheat reallocation units, play a pivotal role in upholding superior\nair quality and human well-being across diverse environments ranging\nfrom international space stations and pharmacies to granaries and\ncultural relic preservation sites, and to commercial and residential\nbuildings. The adoption of sorbent water as the working pair and low-grade\nrenewable or waste heat in adsorption-driven air-conditioning presents\na state-of-the-art solution, notably for its energy efficiency and\neco-friendliness vis-à-vis conventional electricity-driven\nvapor compression cycles. Here, we introduce a rational π-extension\nstrategy to engineer an ultrarobust and highly porous zirconium metal–organic\nframework (Zr-MOF). This MOF sorbent showcases hysteresis-free S-shaped\nwater sorption isotherms, characterized by a rapid ascent within the\n40–60% relative humidity range with a working capacity of 0.63\ng g<sup>–1</sup>, thus facilitating intelligent indoor humidity\nregulation. Moreover, we demonstrate, for the first time, that this\nmaterial with such distinctive isotherms can yield a 10 °C temperature\nlift between ambient and chiller output with a high cooling capacity\nof 336 kW h m<sup>–3</sup> per cycle, even at exceptionally\nlow driving temperatures (below 50 °C), while also delivering\na substantial coefficient of performance of 0.96. This material is\namenable to scale-up and is chemically ultrastable that can endure\nstrong acids and be cycled for at least 200 runs without compromising\nany of its capacity. These exceptional attributes signify the viability\nof this material as a pragmatic alternative for deployment in energy-efficient\ndesiccant air-conditioning systems, particularly in hot and humid\nclimatic regions.