A metal\u2013organic framework for efficient water-based ultra-low-temperature-driven cooling

Dirk Lenzen,Mohammad Wahiduzzaman,Sebastian-Johannes Ernst,Xiaodong Zou,Dominik Fröhlich,Guillaume Maurin,Jingjing Zhao,Hongyi Xu,Norbert Stock,Christoph Janiak,Stefan Henninger,Hans-Jörg Bart,A Ken Inge

doi:10.1038/s41467-019-10960-0

Abstract

Efficient use of energy for cooling applications is a very important and challenging field in science. Ultra-low temperature actuated (Tdriving < 80 °C) adsorption-driven chillers (ADCs) with water as the cooling agent are one environmentally benign option. The nanoscale metal-organic framework [Al(OH)(C6H2O4S)] denoted CAU-23 was discovered that possess favorable properties, including water adsorption capacity of 0.37 gH2O/gsorbent around p/p0 = 0.3 and cycling stability of at least 5000 cycles. Most importantly the material has a driving temperature down to 60 °C, which allows for the exploitation of yet mostly unused temperature sources and a more efficient use of energy. These exceptional properties are due to its unique crystal structure, which was unequivocally elucidated by single crystal electron diffraction. Monte Carlo simulations were performed to reveal the water adsorption mechanism at the atomic level. With its green synthesis, CAU-23 is an ideal material to realize ultra-low temperature driven ADC devices.

Highlights

Efficient use of energy for cooling applications is a very important and challenging field in science
After an additional washing step with 200 mL water under stirring and reflux, filtration and drying, 4.5 g of a white powder was obtained (84% yield based on H2TDC)
Thermogravimetric analysis, infrared spectroscopy, elemental analysis, and nitrogen sorption measurements are in good agreement with the expected values for the ideal composition (Supplementary Figs. 2–4, Supplementary Table 2)

Summary

Introduction

Efficient use of energy for cooling applications is a very important and challenging field in science. This is the crucial step regarding efficiency and it is performed by heating the active material to desorb water (driving temperature). With smaller temperature differences between the adsorption and desorption step, the switching process becomes faster and more energy efficient since less energy is consumed to overcome the thermal capacities (adsorbent, binder, heat exchanger, piping...) while heating and cooling.

Results

Conclusion