Research on improvement in the efficiency of the GM refrigerator.


In moving toward a hydrogen energy society, a key focus of research has been on the development of fuel-cell electric vehicles. As the volume and weight density of liquid hydrogen are large, liquid hydrogen is seen as the preferred storage method over gaseous hydrogen. However, in order to store liquid hydrogen stably over a long period of time with minimal loss of energy, it becomes important to develop an efficient small cryocooler. In contrast, progress toward superconducting systems in recent years has been remarkable. Therefore, improvement in the refrigeration efficiency of 4 K cryocoolers deserves increased consideration. This paper reports on research aimed at improving the refrigeration efficiency of a two-stage GM cryocooler. Because a GM cryocooler operates using Simon expansion, its COP approaches that of the ideal Carnot cycle as the compression ratio is lowered. When investigated with this viewpoint, we have verified that GM refrigeration efficiency rises with reduction of the compression ratio. If the compression ratio is further lowered, refrigeration efficiency will fall rapidly. Thus, by optimization of the compression ratio of a GM cryocooler, it has been verified that refrigeration efficiency can be improved significantly. Application of the results of this research have the potential of sharply reducing the energy consumption of liquid hydrogen and superconducting systems.


  • Original title: Research on improvement in the efficiency of the GM refrigerator.
  • Record ID : 2008-1047
  • Languages: English
  • Publication date: 2006/06/14
  • Source: Source: Proc. 14th int. Cryocooler Conf., Annapolis, MD
    187-193; fig.; tabl.; 7 ref.