Power saving of large-scaled cryogenic system for fusion device

For the purpose of reducing the power consumption of a cryogenic system for an experimental nuclear fusion system, we studied a new cryogenic system which includes an additional auxiliary gas cooling system. The power consumption of the helium compressor will be reduced by cooling down the suction gas temperature of helium compressor, and the power reduction becomes higher than the power used for the additional auxiliary gas cooling system. Further, much higher power reduction will be realized by adding a chemical heat pump driven by the waste heat of the helium compressor because the chemical heat pump requires small power against normal type heat pump. We studied the improvement of efficiency of this new system comparing to the CERN's 18 kW cryogenic system because this system will be the design basis of ITER's cryogenic system. As the result of study, some 11% of power consumption can be saved using this new cycle compared to a conventional system when the helium gas suction temperature of the compressor is 235 K. (author)