Charge–discharge cycling, flowthrough cooling and para-ortho conversion for cooling bulk hydrogen storage tank filled with MOF-5

We numerically studied the thermal and storage performance of the 20 m3 bulk hydrogen storage reservoir filled with MOF-5. In this study, at first, we present two methods such as charge–discharge cycles and flowthrough cooling for cooling the 20 m3 bulk hydrogen storage reservoir filled with MOF-5. The results show that cooling of room temperature maintained bulk storage reservoir to 80 K is a time and energy consuming process when flowthrough cooling alone is considered as a cooling option compared to charge–discharge cycles. Further, the effect of mass flow rate on heat removal from the system during the flowthrough stage is investigated. The result shows that high mass flow rate accelerates the heat removal and cool the tank in a short period of time. Also, the effect of para-ortho conversion together with flowthrough cooling on temperature reduction in the tank is studied. The results shows that instantaneous para-ortho conversion together with flowthrough cooling enhances not only the heat removal from the system but the storage capacity also. The hydrogen mass loss during the 10 days dormancy stage is calculated and found that 28 kg of hydrogen is lost during the dormancy stage.