Improving the cooling efficiency of cryo-compressed hydrogen based on the temperature-distributed method in regenerative refrigerators

Enhancing the cooling efficiency of hydrogen storage method is crucial for the advancement of cryo-compressed hydrogen (CcH2) storage systems. The conventional regenerative method with high-low temperature cycles results in significant exergy losses. Thus, this paper proposed a temperature-distributed method to mitigate the exergy loss by using real gas effects. The proposed method extracts the temperature-distributed refrigeration power from 80 to 100 K up to about 273.15 K when using nitrogen, oxygen or argon as the refrigerant, thereby reducing the temperature difference of cooling process for the distributed sensible heat of CcH2. In an ideal regenerator with a reduced pressure range of 4.0–16.0, the refrigeration power reaches 2.7–12.5 times greater than that at the cold end. O2 exhibits the minimum entropy generation in the cooling unit, and the specific power consumption (SPC) is ∼1/3 that of ideal high-low temperature cycles. The calculation results indicate that the distributed method achieves a minimal SPC of 2.72 kWh/kg, which is 30.08 % lower than the SPC with the conventional method. Considering practical working conditions, the distributed method achieves an SPC of 5.74 kWh/kg, still representing a reduction of 33.72 %. This method provides an effective approach for designing efficient and simplified hydrogen cooling system with regenerative configurations.