Adsorption Refrigeration Performance of Shaped MIL-101-Water Working Pair

A new metal-organic framework of MIL-101 was synthesized by hydrothermal method and the powder prepared was pressed into a desired shape. The effects of molding on specific surface area and pore structure were investigated using a nitrogen adsorption method. The water adsorption isotherms were obtained by high vacuum gravimetric method, the desorption temperature of water on shaped MIL-101 was measured by thermo gravimetric analyzer, and the adsorption refrigeration performance of shaped MIL-101-water working pair was studied on the simulation device of adsorption refrigeration cycle system. The results indicate that an apparent hysteresis loop appears in the nitrogen adsorption/desorption isotherms when the forming pressure is 10 MPa. The equilibrium adsorption capacity of water is up to 0.95 kg·kg−1 at the forming pressure of 3 MPa (MIL-101-3). The desorption peak temperature of water on MIL-101-3 is 82 °C, which is 7 °C lower than that of silica gel, and the desorption temperature is no more than 100 °C. At the evaporation temperature of 10 °C, the refrigeration capacity of MIL-101-3-water is 1059 kJ·kg−1, which is 2.24 times higher than that of silica gel-water working pair. Thus MIL-101-water working pair presents an excellent adsorption refrigeration performance.